Patent Publication Number: US-6711401-B1

Title: Wireless centrex call return

Description:
This application is a continuation-in-part of application Ser. No. 09/224,272 filed Dec. 31, 1998 and a C-I-P of Ser. No. 09/223,567 filed Jan. 19, 1999. This application relates to the provisional application Ser. No. 60/114,317 filed Jul. 16, 1999. The complete disclosures of these applications are hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The instant invention relates generally to the field of communication, and more particularly, to the field of personal communications. The present invention articulates methods and systems for extending the benefits of wireless voice and data services to subscribers, especially in business premises and public environments, such as universities and hospitals. Furthermore, the present invention is geared towards providing methods and systems for processing and controlling communications in wireless communications and in a wireless centrex based environment. 
     BACKGROUND 
     The challenges of an increasing mobile workforce have resulted in businesses migrating towards a more flexible and decentralized working environment. These newly evolved environments have created a need for communication systems that must be capable of facilitating untethered communication at any time and any place. Consequently, there is vast growth in emerging technologies that facilitate communication anywhere and anytime. Such technologies are employed in end user devices such as pagers, cellular telephones, and mail systems such as voice mail and e-mail systems. 
     There presently exists both wireline telephone network systems for home and office use and cellular telephone systems for wireless mobile calls anywhere wireless services are offered (i.e., anywhere a user subscribed cellular base station reception can reach), which are interconnected to each other through the Public Switched Telephone Network (PSTN). As such, a user has a choice of contacting other telephone users or being contacted by other telephone users by using either the wireline telephone system or the cellular phone system, each having their own respective detriments. 
     Wireline business telephone service is typically more economical than cellular phone service. However, if a user decides to use a wireline telephone as their only business telephone they can not be immediately contacted if they are not in their own office where their business telephone is physically located. Nor can the user easily make telephone calls while not in his own office or on travel. On the other hand, if a user decides to have a cellular phone as their only business telephone they can be contacted at anywhere at anytime but will likely incur higher costs, e.g., airtime charges, which in total can be higher than using wireline telephone services. In the aggregate the cost of cellular telephone service to all employees of a company is generally cost prohibitive. In addition, a cellular telephone does not typically provide the feature/function of a wireline telephone service (e.g., Integrated Services Digital Network (ISDN) and centrex feature/function). 
     Furthermore, if a user decides to have both a wireline telephone and a cellular phone for their business use, they incur cost for using both systems and experience the inconvenience of having two separate telephones and thus two separate voice mail systems to check for messages. A caller is also inconvenienced by having to call both the user&#39;s wireline telephone number and the user&#39;s cellular telephone to reach the user. 
     Wireline telephone network systems (including ISDN and centrex capabilities) and cellular telephone systems each have various feature/functions available to the user. Therefore, a need exists to provide a wireless centrex system (WCS) having features and functions presently available in existing wireline service and cellular services, as well as offering new feature/functions, while offering low cost telephone service for the working environment. 
     SUMMARY OF THE INVENTION 
     The instant invention addresses this need for an untethered communication systems created by the paradigm shift towards a more flexible and decentralized working environment. The material described in the instant invention discloses a wireless communication platform that provides a solution to the challenge of mobility management by merging and expanding the capabilities of wired and wireless networks. Thus, the present invention includes systems and methods to provide a wireless communication service that has expanded the features/functions available in wireline and cellular telephone systems and the relative cost of the wireline system using a mobile telephone system and service that is added to existing wireline telephone systems equipment, to offer cost effective wireless communications for the working environment. 
     The instant invention includes a wireless centrex system (WCS) that allows a subscriber to use the same standard cellular/PCS telephone in both the wireless centrex system domain as well as the public cellular system domain. In the WCS domain, subscribers can use their cellular/PCS as a cordless-like phone without incurring air-time charges. The WCS has the advantage of providing a working environment mobile telephone system having traditional centrex and PBX type services such as call waiting, call hold, call forwarding, caller ID, three party conference calling, and call messaging. The WCS also includes additional enhanced features like message services used for paging, call screening, call waiting, distinctive ringing, user proactive call handling, automatic callback, call return and speed calling. 
     In general, the present invention is directed towards a method and system for extending the benefits of wireless voice and data systems to a wireless centrex system. The method and system as described in the instant invention, provides flexible software driven support for future generation air interfaces, as well as support for current legacy second generation air interfaces. 
     In traditional centrex systems, subscriber&#39;s locations are fixed, and as a result, the call delivery mechanism to deliver a call to a subscriber is predetermined. However, in a wireless environment, the subscriber has the flexibility to continuously move throughout a specified coverage area. Consequently, there exists a need to provide an intelligent call and message delivery mechanism. The instant invention introduces a novel call delivery mechanism using an Advanced Intelligent Network (AIN) to achieve delivery. This AIN has a Service Switching Point (SSP) which utilizes a triggering mechanism to determine the appropriate call handling treatment for a specific call. As such, the system includes, for example, an existing local digital switch (LDS) as the SSP, an intelligent server (herein referred to as a network server platform (NSP)) coupled to the LDS for processing AIN communications, a plurality of remote digital terminals (RDT) coupled to the LDS, a plurality of intelligent transceivers (herein referred to as voice access ports (VAP)) coupled to the RDT (alternatively: the VAP could be coupled directly to the LDS), and a plurality of mobile stations (MS) which communicate with the VAPs through an air interface (wireless). Although a general WCS configuration with existing wireline centrex equipment has been provided as one preferred embodiment, there are many other configurations possible some of which are shown (e.g., WCS using PBX or having wireless data ports) and the basic system interfaces with other existing systems such as a PSTN and provider internet. 
     In operation, for example, the LDS upon receiving an incoming call with a directory number (DN) is triggered to communicate with a network server platform (NSP) to determine, using AIN, whether the DN has been set up to be associated with a mobile station (MS) and WCS service. The NSP tells the LDS to which of a plurality of VAPs connected to a particular RDT the desired mobile station is presently registered with (connected to via air interface RF channel), and how to route the call to the mobile station having the mobile station identification number (MSIN) associated with the called DN. The various feature/functions provided in the WCS services of the present invention are summarized below. 
     Feature Activation/Deactivation 
     Many of the feature/functions provided in the present invention WCS require selection by the mobile station user. As such, the present invention provides a system and method for a mobile station user to activate and deactivate particular features/functions. For example, the Mobile Station (MS) user dials a feature activation/deactivation code into a mobile station which is then sent to the intelligent transceiver (Voice Access Port (VAP)) over a digital control channel (DCCH) and the VAP sends an origination request message including the feature code to an intelligent server (network server platform (NSP)). The NSP determines whether the particular requested feature is authorized for the particular mobile station requesting the feature and activates the feature if it has been authorized. The NSP returns a message through the Local Digital Switch (LDS) and the VAP to the MS indicating that the feature is either activated or unavailable. If the feature/function code entered into the MS is for deactivation the process is similar except that the NSP checks to see if the feature/function is active and if so, turns the feature/function off. In this case, the NSP returns a message through the Local Digital Switch (LDS) and the VAP to the MS indicating that the feature has been deactivated. 
     Call Hold 
     One feature of the present invention provides enhanced call hold functionality. The WCS service provides call hold/unhold functionality for a wireless communications unit (mobile station (MS)) so that a user can place an active call or an incoming call on hold and retrieve the call later. One aspect of the call hold feature of the present invention allows a user to press a button, key, or key combination and/or button combination on his mobile communications unit (MS) to place an active or incoming call on hold. Further, another aspect of the call hold feature allows a user to press the same or a different button, key, key combination and/or button combination to retrieve the call from hold. The call hold feature may also allow the MS user to play a personalized message to the party placed on hold. 
     A still further aspect of the call hold feature for the present invention allows a mobile phone subscriber to place an incoming call on hold without first having to answer the call. According to one such embodiment, the calling party can be coupled to, for example, a voice processing unit (VPU) to receive a message that indicates the call is on hold and the called party (WCS subscriber) will be with you shortly. Thus, the WCS of the present invention provides a user with the ability to interactively place an incoming call on hold in real time without first answering the call, have the caller automatically instructed that the call is on hold, and to pickup the call sometime in the near future. 
     User Proactive Call Handling 
     Another feature of the present invention provides user proactive call handle (UPCH) functionality and capability. This feature allows a mobile telephone user to proactively handle a call in an intelligent wireless communications system. A communications management methodology according to the present invention allows a user to proactively handle calls destined to the user&#39;s terminal, e.g., a mobile station MS. One aspect of this feature allows a user to process and terminate an incoming call in real time. 
     According to an illustrative embodiment of the present invention, a subscriber is notified of an incoming call via a Short Message Service (SMS) message with caller ID or a user alert, such as a tone or ringing. Upon receipt of the alert, the subscriber may select from a series of options, how to process and terminate the incoming call. For example, if an incoming call is of high priority and requires immediate attention, the subscriber may decide to answer the call immediately. If the subscriber decides that the call does not require immediate attention, he may opt to provide a delayed answer. Such a delayed answer option can involve connecting the call to an announcement prior to answering the call. Still further, if neither of the prior options is suitable, then the subscriber may opt to send the call to a voice mail system, from which a recorded message can later be retrieved. Yet another option of terminating the call is to forward the call to another phone. In the event that the subscriber decides that the incoming call should not be answered, the subscriber may choose to reject the call. If the subscriber decides that none of the aforementioned options should be proactively taken, then a default option can be used to terminate the call. Such a default option may include, but is not limited to, forwarding the call, delaying the answer, sending the call to a voice mailbox, or rejecting the call. 
     Another aspect of the UPCH feature provides the ability to delay allocation of the voice channel to a called party until when, if at all, the incoming call to the called party requires a voice channel. This is carried out by allowing a called party to receive notification of an incoming call over the control channel and to return the selection of the call handling options upstream over the control channel. Thus, a voice channel need not be allocated until the called party decides to answer the call. This can be beneficial in wireless environments to prevent the unnecessary allocation of voice channels. Once the called party needs a voice channel, the incoming call has priority for available voice channels. 
     Call Transfers 
     Yet another feature of the present invention provides enhanced call transfer functionality. The WCS services provides call transfer functionality for a wireless communications unit (mobile station (MS)) so that a user can transfer an active call to another DN, i.e., a transfer-to DN, that is within or outside the WCS. The MS user is provided a quick, user friendly means to transfer an active call to another DN. According to one variation of the call transfer feature/function the MS user enters digits for a call transfer feature code and digits for the transfer-to DN, which are forwarded via a unique Feature Request message to an NSP to initiate the call transfer feature. After an NSP verifies that the MS is authorized to use the call transfer feature, a unique Transfer message is provided, an announcement is played indicating that call transfer is being initiated, and the active call is placed on hold while a call setup is performed between the VAP (associated with the MS requesting a call transfer) and the transfer-to DN (which may be associated with either a PSTN or another MS). 
     In some situations the transfer-to DN may be busy or may not be answered. In such cases, before the call to the transfer-to DN is answered, the MS user can enter another key sequence (a button, key, or key combination and/or button combination) to end the call transfer and retrieve the call on hold. On the other hand, when the call to the transfer-to DN is answered a unique Transfer Result message is sent to the NSP indicating that the call has been answered and the MS user can enter a key sequence which instructs the WCS to complete the call transfer 
     Caller ID 
     Still another feature of the present invention provides enhanced caller identification (caller ID) functionality. One feature of the present invention provides enhanced caller identification (Caller ID) functionality. The WCS service provides Caller ID functionality for a wireless communications unit (mobile station (MS)) so that a user can determine a caller&#39;s identity such as the calling party&#39;s directory number and location for an incoming or active call and decide how to handle the incoming call, e.g., answer, not answer, forward to voice mail, etc. One aspect of the Caller ID feature of the present invention allows display on the MS of the originating directory number (Calling Party Number) and identity for an incoming and/or active call, even if the call originates from another MS. Another aspect of the Caller ID feature of the present invention provides the location and identity of the called MS  101  to the calling party and displayed on the calling party&#39;s MS  101  during an active call. In either case, a Network Server Platform (NSP) provides the parties desk top phone directory number (DN) as their telephone number for Caller ID rather than the forward directory number (FDN) associated with a voice access port (VAP) which the MS is presently associated. 
     A further aspect of the Caller ID feature provides that the calling party may be initially coupled to, for example, a voice processing unit (VPU) including voice recognition capabilities, so that the calling party can provide their name or other information which will be displayed on the MS of the called party. A still further aspect of the Caller ID feature allows display on the MS  101  of additional information about the calling or called party, for example their address, building number, company affiliation, etc. for an incoming or active call. The MS  101  user can also disable the caller ID on a call-by-call basis. Thus, the WCS of the present invention provides a MS  101  user with the ability to know the identity of the calling persons before answering a call and the identity and location of a party they are speaking with on an active call, even in the case when the calling party is calling from a WCS MS. 
     Screening Calls 
     An even further feature of the present invention provides call screening functionality and capability. The WCS service provides call screen functionality for a wireless communications unit (mobile station (MS)) so that a user can screen incoming calls to prevent the user from being disturbed by calls from parties with which the user does not wish to speak. One feature of the call screen feature/function of the present invention allows a user to press a button, key, or key combination and/or button combination on the MS to block out an incoming call(s) originating from a telephone number(s) specified by the user. The MS user will specify a list of phone numbers (call screen list) for which incoming calls are to be blocked when received. When any one of the phone numbers on the call screen list is the originating phone number for an incoming call directed to the MS, the system will block that call so that the MS user is not alerted and thus not disturbed. 
     A further feature of the call screen feature/function of the invention enables an MS user to specify how the screened call(s) will be handled. The MS user can specify that the screened call may be, for example, sent to an answering service such as a voice mail system, provided an announcement selected by the MS user, or dropped without any announcement. 
     Another feature of the call screen feature/function enables the MS user to enter a phone number to the screen call list of phone numbers by either manually entering each digit of the phone number or by indicating that the phone number of the last active call is to be added to the call screen list. In the first case, the MS user can enter a phone number to the call screen list by entering, for example, the call screen feature code followed by the phone number to be blocked. In the second case, the MS user can dynamically enter a phone number in the call screen list by entering, for example, a particular key or entering the call screen feature code without any phone number. The WCS will then determine the phone number of the last active phone call and add that phone number to the call screen phone number list so that any incoming calls from that phone number will be blocked. 
     Call Forwarding 
     Further aspects of the present invention provide a means for forwarding calls to another number in a WCS  140  system. The number that the call is being forwarded to may be within or outside the WCS  140  system. There are several modes of call forwarding that are available. For example, a call may be unconditionally forwarded, forwarded after a certain number of rings or upon the passage of a certain amount of time, forwarded in response to the called MS  101  being busy, and/or forwarded only during one or more selected time periods. Moreover, one or more of these call forwarding modes may be used in any combination. For instance, a call may be forwarded only during the weekend and only after a predetermined number of rings. The call forwarding feature(s) may be activated/deactivated directly from the MS  101  to be called, from another MS, via a network such as a conventional telephone network or the Internet, and/or by calling a Customer Care Center (CCC) representative. 
     Accordingly, an aspect of the present invention is directed to systems and methods for forwarding an incoming call, the call originating from a first communication device and being directed to a directory number of a wireless centrex system. For example, the systems and methods may generate a message by a local digital switch in response to the call, and determine by a network server platform, responsive to receiving the message, whether the call should be forwarded. The call may be either forwarded to the second communication device responsive to the network server platform determining that the call should be forwarded, or routed to a wireless mobile station having a forward directory number associated with the directory number responsive to the network server platform determining that the call should not be forwarded. 
     In a further aspect of the present invention, the systems and methods may determine by the local digital switch whether the wireless mobile station is busy with another call. The call may be either forwarded by the local digital switch to the second communication device responsive to determining that the wireless mobile station is busy, or routed to the wireless mobile station responsive to determining that the wireless mobile station is not busy. 
     In yet a further aspect of the present invention, the systems and methods may generate a current time and determine whether the current time is between a begin time and an end time. The call may either be forwarded to the second communication device responsive determining that the current time is between the begin time and the end time, or routed to the wireless mobile station responsive to determining that the call should not be forwarded. 
     In a still further aspect of the present invention, the systems and methods may alert the wireless mobile station and count a predetermined amount of time in response to the call. The call may be forwarded to the second communication device responsive to the predetermined amount of time being counted. 
     Call Waiting 
     The present invention also provides a method for call waiting in a WCS system. In particular, the call waiting functionality allows a user of a mobile station (MS) to be notified of an incoming call when the MS is being used. That is, when an existing call between the MS user and another party is ongoing, the MS user can be notified of another call directed to the MS. The call waiting feature also allows the MS user to place an ongoing call on hold and answer the incoming call. Further, the MS user may switch back and forth between the calls. Currently, there is no known call waiting service in a WCS system. 
     Distinctive Ringing 
     The present invention also provides a method for distinctive ringing in a WCS system. In particular, the distinctive ringing functionality allows a user of a mobile station in a WCS system to receive a distinctive ring for a call originated from a communications unit having a particular directory number (DN). A user can select one or more DNs for which a distinctive ring will be received when a call is originated from a unit assigned the selected DN. 
     Returning Calls 
     Still another feature of the present invention provides enhanced call return functionality. The present invention overcomes the drawbacks associated with existing systems by providing a call return functionality for wireless communication systems. The invention enables automatically placing the phone number of an incoming call, where the phone number is not unknown or security-protected, in a memory so that the call may be automatically dialed when it is convenient for the person to return the call. 
     A user may wish to handle calls from different parties differently. Thus, in one embodiment, where more than one incoming call is received, the phone numbers for the incoming calls may be stored in a first-in, last-out viewing order on a display. Alternatively, the phone numbers for the incoming calls may be stored in a first-in, first-out viewing order or any predetermined order. In addition, prior to the wireless call return processor initiating dialing the phone number for the incoming call, the user may utilize the wireless call return processor to select which incoming call he wishes to return first by moving a first displayed phone number to the end of a list of phone numbers of incoming calls received and if desired, repeating this action. Alternatively, if the user desires to delay briefly returning the call associated with the first displayed phone number call, the user may transpose the first displayed phone number with a next phone number of the incoming calls received. Again, this action may be repeated as desired. 
     Where the phone number is unknown or is security-protected so that display of the phone number is blocked, the display may indicate that the phone number for the incoming call is unable to be displayed. Alternatively, a voice prompt, a short message, or a predetermined tone may indicate that the phone number for the incoming call is unknown or unable to be displayed. 
     Automatic Callback 
     Another feature of the present invention provides enhanced automatic callback functionality. Present wireless handsets do not provide for automatic callback to free the user from having to redial, perhaps repeatedly, a number in order to complete a call. Clearly, there is a need for a system, wireless apparatus and method for providing automatic callback for a user in a wireless communication system when a called number is unavailable. 
     The present invention overcomes the drawbacks associated with existing systems by providing an automatic callback functionality for wireless communication systems. The invention provides for automatically redialing the phone number of a call when a number called by a wireless user is busy, thus permitting the wireless user to continue with other work and to answer the phone when the callback succeeds in connecting the call. 
     When the call is connected, the wireless system may generate a voice prompt via the wireless apparatus, a predetermined tone, an alert light or the like, to notify the wireless user that the callback call is connected. The wireless user may answer the call immediately, may press a button or use a verbal command or commands to put a present call on hold and switch to the callback call. If the wireless user chooses to put the callback call on hold, a pre-recorded message from the wireless system may be played for the callback caller to alert him that the wireless user will be answering his call in a very short time. 
     Speed Calling 
     The present invention also provides a method for speed calling in a WCS system. In particular, the speed calling functionality allows a user of a mobile station in a WCS system to create a list of at least one phone number for which the subscriber utilizes a speed calling code to call at least one phone number. A subscriber can then call a selected phone number by entering a provisioned speed calling code rather than a longer telephone number. 
     Conference Calls 
     Adding A Party To An Existing Call 
     Still another feature of the present invention provides enhanced conference call functionality. The WCS service provides conference call functionality for a wireless communications unit (mobile station (MS)) so that a user can connect additional parties to an active call with a party within or outside the WCS. The MS  101  user is provided a quick, user friendly means to add another party to an active call. Further, the MS  101  user is provided a quick, user friendly means to retrieve an original call before a third party answers a call during a conference call setup. 
     According to one variation of the conference call feature/function, the MS  101  user enters digits for a conference call feature code and digits for the conference-with DN, which are forwarded via a Feature Request message to an NSP  106  to initiate the conference call setup procedure. Once the NSP  106  verifies that the MS  101  user is authorized to use the conference call feature, a Feature Request Acknowledgement message containing instructions to play a voice prompt to the MS  101  is provided to a VAP  103 , an announcement is played indicating that a conference call is being initiated, and the active call is placed on hold while a conference call setup is performed between the VAP  103  (associated with the MS  101  requesting a conference call) and the conference-with DN (associated with, for example, either a PSTN or another MS). After the third party answers, the MS  101  user can press another key, for example the “send” button on the MS  101 , to re-connect the original party(ies) to the conference call. However, if the WCS is unable to connect the third party with the MS  101  user, the MS  101  user is prompted and notified of the failure to connect allowing the MS  101  user to terminate the conference call connection procedure by pressing another key, for example the “send” button on the MS  101 , to recover the previously active call with the original party(ies). 
     In some situations the conference-with DN may be busy or may not be answered, or the MS  101  user may simply decide they no longer wish to connect the third party to the conference call. In such cases, before the call to the conference-to DN is answered, the MS user can decide to end the conference call connection procedure without prior system prompt by entering another key sequence (a button, key, or key combination and/or button combination) to end the conference call transfer connection procedure and retrieve the original call on hold. For example, the MS  101  user could press the “send” key twice within a short period of time. In response, the conference call connection procedure will cease, the call setup with the third party will be disconnected, and the original call will be retrieved. 
     Deleting A Party From An Existing Call 
     Still another feature of the present invention provides enhanced conference call functionality. The WCS provides conference call functionality for a wireless communications unit (mobile station (MS)) so that a user can connect and disconnect parties to an active call with a party within or outside the WCS. The MS  101  user is provided a quick user friendly means to delete a party from an active conference call. 
     According to one variation of deleting a party from a conference call feature/function, the MS  101  user enters a party drop feature message and the VAP  103  determines that the MS  101  user is requesting that the last party added to a conference call be dropped. The VAP  103  will then request the LDS  104  to drop the last added call of the current conference call. The LDS  104  proceeds by sending the necessary messages to have the last added call released from the conference call. For example, the MS  101  user could press the “send” key twice within a short period of time. In response, the last added call to an active conference call connection procedure will be dropped by the LDS  104 . 
     WCS As a Wireless PBX System 
     Another feature of the present invention includes a WCS which is a Wireless PBX system. In this case, the system includes a Intelligent Wireless Controller (IWC) that connects to a Customer Premises PBX and an NSP. The IWC and PBX will provide various functions performed by the LDS and RDT found in a typical WCS. 
     WCS with Wireless Voice and Data 
     Yet another feature of the present invention includes wireless data capability with the WCS. In this case, laptop computers equipped with a transceiver interface with Data Access Ports (DAP) connected to an Integrated Wireless Communication Controller to provide a wireless data system integrated with the WCS Voice Access Ports (VAP) and a LAN. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings in which like designations represent like parts, and in which: 
     FIGS. 1A-1C illustrates an exemplary wireless centrex system platform architecture. 
     FIG. 2 illustrates an exemplary wireless centrex network architecture. 
     FIG. 3 illustrates an exemplary signal flow diagram which demonstrates the registration process which occurs when the mobile station is powered on. 
     FIG. 4 illustrates an exemplary signal flow diagram which demonstrates call origination. 
     FIG. 5 illustrates an exemplary signal flow diagram which demonstrates termination of a call by a mobile station that answers the call. 
     FIG. 6 illustrates an exemplary signal flow diagram which demonstrates termination of a call by a mobile station that went unanswered. 
     FIG. 7 illustrates an exemplary signal flow diagram which demonstrates call termination to a roaming subscriber. 
     FIG. 8 illustrates an exemplary signal flow, diagram which demonstrates intra-local digital switch assisted handoff. 
     FIG. 9 illustrates a communications network for a wireless centrex system executed using a PBX system according an embodiment of the present invention. 
     FIG. 10 illustrates still another communications network for wireless centrex system capability having a wireless voice and wireless data wireless centrex system according to another embodiment of the present invention. 
     FIG. 11 illustrates an exemplary signal flow diagram which demonstrate feature activation/deactivation. 
     FIG. 12 shows a block diagram of illustrative communications network according to yet another embodiment of the present invention. 
     FIG. 13 shows an exemplary signal flow for setting up an incoming call used for call hold/unhold feature, in accordance with an illustrative embodiment of the present invention. 
     FIG. 14A shows a first exemplary call flow for the feature of call hold/unhold during an active call in accordance with an illustrative embodiment of the present invention. 
     FIG. 14B shows a second exemplary call flow for the feature of call hold/unhold during an active call in accordance with another illustrative embodiment of the present invention. 
     FIG. 15 shows another exemplary signal flow for the feature of call hold/unhold of an unanswered incoming call in accordance with an illustrative embodiment of the present invention. 
     FIG. 16 shows an exemplary user proactive call handling signal flow diagram for the activation and deactivation of the UPCH feature in accordance with an illustrative embodiment of the present invention. 
     FIG. 17 shows an exemplary user proactive call handling signal flow diagram for handling an incoming call when the UPCH feature is employed in accordance with an illustrative embodiment of the present invention. 
     FIG. 18 shows an exemplary proactive call handling signal flow diagram for the delay answer call feature in accordance with an illustrative embodiment of the present invention. 
     FIG. 19 shows a signal flow diagram for an exemplary call transfer to a PSTN telephone in accordance with an illustrative embodiment of the present invention. 
     FIG. 20 shows a signal flow diagram for an exemplary call transfer to a mobile station in accordance with an illustrative embodiment of the present invention. 
     FIG. 21A illustrates a flowchart of an origination leg of a Caller ID information retrieval procedure for one preferred embodiment of the present invention. 
     FIG. 21B illustrates a flowchart of a termination leg of a Caller ID information retrieval procedure for one preferred embodiment of the present invention. 
     FIG. 21C illustrates a signal flow diagram for Caller ID information during call origination for one preferred embodiment of the present invention. 
     FIG. 21D illustrates a signal flow diagram for Caller ID information during call termination for one preferred embodiment of the present invention. 
     FIG. 21E illustrates a flowchart of an origination leg of a Caller ID information retrieval procedure for another preferred embodiment of the present invention. 
     FIG. 21F illustrates a flowchart of a termination leg of a Caller ID information retrieval procedure for another preferred embodiment of the present invention. 
     FIG. 21G illustrates a signal flow diagram for Caller ID information during call origination for another preferred embodiment of the present invention. 
     FIG. 21H illustrates a signal flow diagram for Caller ID information during call termination for another preferred embodiment of the present invention. 
     FIG. 22 shows a signal flow diagram for provisioning an exemplary call screen in accordance with an illustrative embodiment of the present invention. 
     FIG. 23 shows a signal flow diagram for dropping a screened call without an announcement for an exemplary call screen in accordance with an illustrative embodiment of the present invention. 
     FIG. 24 shows a signal flow diagram for sending a screened call to a voice mail system for an exemplary call screen in accordance with an illustrative embodiment of the present invention. 
     FIG. 25 shows a signal flow diagram for dropping a screened call after providing an announcement for an exemplary call screen in accordance with an illustrative embodiment of the present invention. 
     FIG. 26 is an exemplary flow chart of the unconditional call forwarding feature of the present invention. 
     FIG. 27 is an exemplary signal flow diagram for signals generated when a call is successfully forwarded using the unconditional call forwarding feature of the present invention. 
     FIG. 28 is an exemplary flow chart of the busy call forwarding feature of the present invention. 
     FIG. 29 is an exemplary signal flow diagram for signals generated when a call is successfully forwarded using the busy call forwarding feature of the present invention. 
     FIG. 30 is an exemplary flow chart of the time-of-day call forwarding feature of the present invention. 
     FIG. 31 is an exemplary signal flow diagram for signals generated when a call is successfully forwarded using the time-of-day call forwarding feature of the present invention. 
     FIG. 32 is an exemplary flow chart of the programmable ring call forwarding feature of the present invention. 
     FIG. 33 is an exemplary signal flow diagram for signals generated when a call is successfully forwarded using the programmable ring call forwarding feature of the present invention. 
     FIG. 34 illustrates an exemplary embodiment of an Internet web page for activating and/or modifying features according to aspects of the present invention. 
     FIG. 35 shows an exemplary call flow diagram for the call waiting functionality according to an illustrative embodiment of the present invention. 
     FIG. 36 shows an illustrative flow diagram for the call waiting service feature according to an embodiment of the present invention. 
     FIG. 37 shows an exemplary call flow diagram for the actual implementation of the distinctive ringing feature according to an illustrative embodiment of the present invention. 
     FIG. 38 is a signal flow chart showing signaling flow steps for an illustrative embodiment implementing a call return in accordance with the present invention. 
     FIG. 39 illustrates one embodiment of steps for implementing a method for automatically returning an incoming call in a wireless communication system in accordance with the present invention. 
     FIG. 40 is a block diagram of a wireless apparatus utilized for implementing the method of the present invention in a wireless communication system. 
     FIG. 41 is a flow chart showing another embodiment of steps in accordance with the method of the present invention. 
     FIG. 42 is a block diagram of one embodiment of a wireless communication platform for providing automatic wireless call return in accordance with the present invention. 
     FIG. 43 is a signal flow chart showing signaling flow steps for an illustrative embodiment implementing the automatic callback functionality in accordance with the present invention. 
     FIG. 44 is a signal flow chart showing one embodiment of signaling flow when a mobile station MS moves from an original serving voice access port VAPo to a new voice access port VAPn before a call is connected. 
     FIG. 45 is a flow chart showing one embodiment of steps of a method in accordance with a preferred embodiment of the present invention. 
     FIG. 46 is a block diagram of a wireless apparatus utilized for implementing the method of the present invention in a wireless communication system. 
     FIGS. 47A-47C represent a flow chart showing another embodiment of steps for implementing the automatic callback feature of the present invention wherein the wireless user is permitted to automatically re-dial the last number dialed via a queuing process that sets up the call when the called line is idle. FIG. 47A illustrates steps during call establishment/activation; FIG. 47B illustrates steps for one embodiment implementing the NSP procedure. FIG. 47C illustrates steps for one embodiment implementing the VAP procedure. 
     FIG. 48 is a flow chart showing another embodiment of steps in accordance with the method of the present invention. 
     FIG. 49 is a block diagram of one embodiment of a wireless communication platform for providing wireless automatic callback in accordance with the present invention. 
     FIG. 50 shows an exemplary call flow diagram for the actual implementation of the speed calling feature according to an illustrative embodiment of the present invention. 
     FIG. 51 is a first partial process flow diagram for a conference call procedure in accordance with an illustrative embodiment of the present invention. 
     FIG. 52 is a second partial process flow diagram, related to the first partial diagram of FIG. 51, for a conference call procedure in accordance with an illustrative embodiment of the present invention. 
     FIG. 53 shows a signal flow diagram for an exemplary three-way conference call for adding a PSTN telephone to an existing PSTN-MS call in accordance with an illustrative embodiment of the present invention. 
     FIG. 54 shows a signal flow diagram for an exemplary three-way conference call for retrieving an original call when a third party could not be connected to an existing PSTN-MS call for a conference call in accordance with an illustrative embodiment of the present invention. 
     FIG. 55 shows a signal flow diagram for a three-way conference call for enabling an MS  101  user to initiate retrieval of an original call with a PSTN telephone of an existing PSTN-MS call without WCS prompting before a conference call is established in accordance with an illustrative embodiment of the present invention. 
     FIG. 56 shows a signal flow diagram for an exemplary deleting (dropping) of a last added party from an active conference call for a PSTN telephone connection leaving an PSTN-MS two-way call, in accordance with an illustrative embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     I. Acronyms and Short Hand Notations 
     Throughout the disclosure of the instant invention, several acronyms and short hand notations are used to aid in the understanding of certain concepts pertaining to the associated system and services. These acronyms and shorthand notations are intended solely for the purpose of providing an easy methodology of communicating the ideas expressed herein, and are in no way meant to limit the scope of the present invention. The following is a list of these acronyms: 
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 AIN 
                 Advanced Intelligent Network 
               
               
                 ALS 
                 AT&amp;T Local Services 
               
               
                 B-Channel 
                 Bearer Channel 
               
               
                 ATM 
                 Asynchronous Transfer Mode 
               
               
                 BER 
                 Bit Error Rate 
               
               
                 BRI 
                 Basic Rate Interface 
               
               
                 BS 
                 Base Station 
               
               
                 CB 
                 Communication Bus 
               
               
                 CSC 
                 Customer Service Center 
               
               
                 CLASS 
                 Custom Local Area Signaling Services 
               
               
                 DCCH 
                 Digital Control Channel 
               
               
                 DAP 
                 Data Access Port 
               
               
                 D-Channel 
                 Data Channel 
               
               
                 DN 
                 Directory Number 
               
               
                 DPU 
                 Directed Call Pickup with Barge-in 
               
               
                 DS1 
                 Digital Service Level 1 
               
               
                 DS3 
                 Digital Service Level 3 
               
               
                 DSP 
                 Digital Signal Processor 
               
               
                 DTC 
                 Digital Traffic Channel 
               
               
                 DTMF 
                 Dual Tone Multi-Frequency 
               
               
                 DVCC 
                 Digital Verification Color Code 
               
               
                 EIA 
                 Electronic Industries Alliance 
               
               
                 FAC 
                 Feature Activation Code 
               
               
                 FACCH 
                 Fast Associated Control Channel 
               
               
                 FDC 
                 Feature Deactivation Code 
               
               
                 FDN 
                 Forward Directory Number 
               
               
                 GR 303 
                 Generic Requirement 303 
               
               
                 IDT 
                 Integrated Digital Terminal/Switch 
               
               
                 IP 
                 Internet Protocol or Intelligent Peripheral 
               
               
                 IS-136 
                 Interim Standard 136 
               
               
                 ISDN 
                 Integrated Services Digital Network 
               
               
                 ISP 
                 Internet Service Provider 
               
               
                 ISUP 
                 ISDN User Part 
               
               
                 ISUP IAM 
                 ISDN User Part Initial Address Message 
               
               
                 ISUP ACM 
                 ISDN User Part Address Complete Message 
               
               
                 ISUP ANM 
                 ISDN User Part Answer Message 
               
               
                 IWC 
                 Intelligent Wireless Controller 
               
               
                 LAN 
                 Local Access Network 
               
               
                 LDS 
                 Local Digital Switch 
               
               
                 MAHO 
                 Mobile Assisted Handoff 
               
               
                 MIN 
                 Mobile Identification Number 
               
               
                 MS 
                 Mobile Station 
               
               
                 MSID 
                 Mobile Station Identification 
               
               
                 MSC 
                 Mobile Switching Center 
               
               
                 NEL 
                 Next Event List 
               
               
                 NSP 
                 Network Server Platform 
               
               
                 OAM&amp;P 
                 Operations, Administration, Maintenance, and Provisioning 
               
               
                 OC3 
                 Optical Carrier Level 3 
               
               
                 OC12 
                 Optical Carrier Level 12 
               
               
                 PAD 
                 Packet Assembler/Disassembler 
               
               
                 PBX 
                 Private Branch Exchange 
               
               
                 PCH 
                 Paging Channel 
               
               
                 PCS 
                 Personal Communications Service 
               
               
                 POTS 
                 Plain Old Telephone Service 
               
               
                 PRI 
                 Primary Rate Interface 
               
               
                 PSID 
                 Private System Identification 
               
               
                 PSTN 
                 Public Switched Telephone Network 
               
               
                 Q.931 
                 Signaling Protocol Message Structure 
               
               
                 RDATA 
                 Relay data (Subfield of IS-136 message) 
               
               
                 RDT 
                 Remote Digital Terminal 
               
               
                 RSSI 
                 Received Signal Strength Indicator 
               
               
                 SC 
                 Self Configuration 
               
               
                 SCP 
                 Service Control Point 
               
               
                 SM 
                 Short Message 
               
               
                 SMDPP 
                 Short Message Delivery Point = To Point 
               
               
                 SMS 
                 Short Message Service 
               
               
                 SMS 
                 Service Management System 
               
               
                 SMSCH 
                 Short Message Service Channel 
               
               
                 SNMP 
                 Signaling Network Management Protocol 
               
               
                 SONFT 
                 Synchronous Optical Network 
               
               
                 SPACH 
                 SMS Point-to-point Messaging, Paging, and 
               
               
                   
                 Access Channel 
               
               
                 SS7 
                 Signaling System 7 
               
               
                 SSP 
                 Service Switching Point 
               
               
                 STP 
                 Signal Transfer Point 
               
               
                 STP 
                 Shielded Twisted Pair 
               
               
                 TAT 
                 Termination Attempt Trigger 
               
               
                 TCP/IP 
                 Transmission Control Protocol/Internet Protocol 
               
               
                 TCAP 
                 Transactional Capabilities Application Part 
               
               
                 TDMA 
                 Time Division Multiple Access 
               
               
                 TIA 
                 Telecommunications Industry Association 
               
               
                 UPCH 
                 User Proactive Call Handling 
               
               
                 VAP 
                 Voice Access Port 
               
               
                 VMS 
                 Voice Message System 
               
               
                 VPU 
                 Voice Processing Unit 
               
               
                 WCS 
                 Wireless Centrex System 
               
               
                 WCSD 
                 Wireless Centrex System Database 
               
               
                 X.25 
                 Cross .25 (Data Packets) 
               
               
                   
               
            
           
         
       
     
     Further, various telecom technical terms are used throughout this disclosure. A definition of such terms can be found in; H. Newton, Newton&#39;s Telecom Dictionary, 14 th  Expanded Edition (1998). These definitions are intended for providing a clearer understanding of the ideas disclosed herein and are in no way intended to limit the scope of the present invention and thus should be interpreted broadly and liberally to the extent allowed by the art and the ordinary meaning of the words. 
     II. General Overview of Wireless Centrex System Services 
     An illustrative methodology for implementing an intelligent wireless communications system according to the present invention will now be described below. While the systems and methods described below relate to a traditional cellular phone system or a wireless centrex system, it is to be understood that the present invention can be applied to all types of wireless communications systems including, but not limited to, satellite systems, micro cellular systems, personal communications services, and other mobile communication systems. Also, other types of personal communications devices can be implemented in these systems including, but not restricted to, a portable television, a wireless videophone, and a pager. Also, it is to be understood that the present invention can be applied to any type of wireless network, and that the description below is an illustrative embodiment for a system employing the IS-136 ELA/TIA Interim Standard. 
     In one exemplary embodiment of the instant invention, the wireless centex system is deployed in an in-building environment with various communication interfaces strategically located throughout the building to provide service within the building. In such an in-building environment, the mobile station (MS) assumes the characteristics of a desktop phone with all the Centrex capabilities being available to the mobile user, plus the added advantage of mobility. A network of picocells served by Voice Access Ports (VAPs) are located within the building and provides the cellular IS-136 air interface. The VAPs are intelligent base stations having ISDN BRI connectivity to a local digital switch (e.g., Lucent 5ESS, Nortel DMS-100). FIGS. 1A,  1 B, and  1 C each show an exemplary VAP  103 A connected to a Remote Digital Terminal (RDT)  102  via an ISDN BRI interface  2 . Hereinafter, references to FIGS. 1A through 1C will be referred to as FIG. 1, and have a common numbering scheme illustrating the various exemplary elements. 
     In fact, the same numbering will be used throughout the figures for like elements. The Network Server Platform (NSP)  106  is an adjunct and can be co-located with a switch (LDS  104 ) to manage the VAPs and call processing control of the MS and provide the cellular (IS-136) operations for the VAPs. In one embodiment, when a call arrives for a subscriber to their POTS desktop phone  108  and it is not answered, the LDS  104  working in conjunction with the NSP  106  and the VAP  103 A will forward the call to the subscriber&#39;s mobile station  101 A over the VAP&#39;s ISDN B-channel  2  and the IS-136 air interface  3 . The WCS system, therefore, offers the capability of a WCS subscriber being reached anytime anywhere within the cell area of the WCS picocells. Further, if a WCS subscriber also subscribes to a macro cellular system the call will be handed off to the macro cellular system local Base Station (BS) when the subscriber leaves the WCS picocell areas. 
     The ISDN BRI lines  2  connecting the VAPs  103 A and  103 B to the switch carry the signaling traffic on the D-channel (data channel) and the voice traffic on the B-channel (bearer channel). The D-channel utilizes the Q.931 protocol to establish a voice call on the B-channel with the LDS  104 . The D-channel also carries signaling messages (X.25 packets) between the VAPs  103 A and  103 B and the NSP  106 . An X.25 packet connection is used to interconnect LDS  104  to NSP  106  and carry packets routed by the LDS  104  between the VAPs  103 A and  103 B and the NSP  106 . The connection to the LDS  104  is not limited to a X.25 data packet connection, but may be any connection supported by the LDS  104 , and having an interworking function with the X.25 protocol. These packets contain messages pertaining to call processing of the IS-136 interface as well as OA&amp;M messages on the VAPs. 
     In one exemplary operation of the WCS, when a call arrives at the subscriber&#39;s desktop phone  109 , if the user does not answer, the switch will use AIN triggers to request additional routing instructions from the NSP  106 . The NSP  106  will locate the subscriber&#39;s MS  101  and direct the LDS  104  to forward the call to the VAP  103  servicing the subscriber&#39;s MS  101 . The NSP  106  will also inform the VAP  103  of the incoming call via messaging on the D-channel and direct the VAP  103  to establish the IS-136 air link to the MS  101  in order to alert the user. When the user answers on their MS  101 , the call is completed over the VAP&#39;s  103  ISDN B-channel and the IS-136 air interface. 
     In accordance with the principles of the invention, whenever a subscriber originates a call, the NSP will work in conjunction with the LDS  104  and the VAP to establish the RF link and the ISDN B-channel connectivity to the switch. The switch will then route the call to the proper destination. When a subscriber moves from picocell (e.g., VAP  103 A service area) to picocell (e.g., VAP  103 B service area), the NSP  106  will inter-work with the switch and the VAPs and use the ISDN Directed Call Pickup with Barge-In to enable the seamless handoff. For example, when the MS  101 A is on an active call served by VAP  103 A, and is moving into the region served by VAP  103 B, the NSP  106  will direct VAP  103 B to barge-in on the call on VAP  103 A. This temporarily establishes a 3-way call and the NSP  106  will then direct VAP  103 A to disconnect from the call, thereby leaving the active call to be served by VAP  103 B and completing the handoff. This is advantageous since the procedure ensures that there is no noticeable interruption of the call on the network side. 
     In accordance with the principles of the instant invention, an exemplary network platform architecture of a wireless centrex system (WCS) is illustrated in FIG.  1 . The wireless centrex system disclosed therein, functions as a private wireless system which is not interconnected to a public macro cellular system. However, the WCS system could also be interconnected to a public macro cellular system. The wireless access platform provides a cordless-like, anywhere, anytime communications for indoor, business or campus-type environments. The key system elements of the WCS platform architecture are the Local Digital Switch (LDS)  104 , the Remote Digital Terminal (RDT)  102 , the Network Server Platform (NSP)  106 , and a wireless interface including one or more of a plurality of Voice Access Ports (VAP)  103 A and  103 B and one or more of a plurality of IS-136 Digital TDMA Cellular/PCS Mobile Stations  101 A and  101 B. Although FIG. 1 illustrates the VAPs  103 A and  103 B being connected to the RDT  102 , the VAPs  103 A and  103 B may also be connected via ISDN BRI lines directly to the LDS  104 , bypassing the RDT  102 . 
     The WCS system of this embodiment may have, for example, the following design attributes. There is one NSP  106  per LDS  104 , although there could be more than one LDS  104  per NSP  106 . The NSPs, (e.g., NSP  106  and NSP  106 A), are interconnected for inter-signaling using TCP/IP across an intranet, e.g., AT&amp;T intranet  112 . Centrex services and features are provided via the LDSs, (e.g., LDS  104  and LDS  104 A) and an SS7 network  111 . A single RDT  102  can provide interconnection of VAPs  103  for the WCS in a single large WCS office or multiple smaller offices as long as an ISDN BRI connection can be made to the VAPs  103 . Further, the WCS system of this embodiment provides smooth handoffs between VAPs  103  using the ISDN Direct Call Pickup with Barge-In (DPU) function. Finally, the WCS system can provide a secure wireless network by only recognizing pre-approved subscribers MS  101  for registration within the picocell area covered by each of its VAPs  103 ; all other cellular phones within the picocell are prohibited from reception/transmission with the VAP&#39;s  103 . 
     The LDS  104  is a TR-08 and/or a GR-303 compatible LDS  104  which employs distributed intelligence, process-oriented software, and coordinated autonomous computing elements to provide a flexible, modular, reliable and robust digital switching system. LDS  104  has generic ISDN switching functions with embedded AIN capabilities and provides network synchronization. The Lucent 5ESS and the Nothem Telecom DMS-100 are exemplary Local Digital Switch (LDSs). The LDS  104  provides a single platform for advanced services including ISDN, Centrex, CLASS, Custom Calling, Advanced Intelligent Network (AIN), and basic bearer Channel (B Channel) call feature applications capabilities. It supports both X.25 packet switched data communication and circuit switched data using, for example, an X.25 Packet Assembler Disassembler (PAD) for signaling between NSP  106  and subtending VAPs (e.g., VAP  103 A and VAP  103 B). The LDS  104  provides the switching fabric, administration, message switching, and call switching functions. The AIN capabilities on the LDS  104  provides AIN software that enables the network provider to create, deploy, and change services to meet customers&#39; requests. The AIN software allows the LDS  104  to act as an AIN Service Switching Point (SSP) to communicate with Service Control Points (SCP) (i.e. NSP  106  in the WCS configuration), and Intelligent Peripherals. This gives the NSP  106  the flexibility to manage call processing on the LDS  104 . The events which activate the AIN triggers must be provisioned so that they occur at specified points in a call where call processing may be interrupted, in order to interact with the NSP  106 . Additionally, the LDS  104  provides a gateway to a PSTN  125 . 
     The Remote Digital Terminal (RDT  102 ) is a digital loop carrier terminal which supports POTS, ISDN, high-speed transport, and all special services—including private lines and PBX trunks. RDT  102  provides voice, data, and signaling transport and multiplexing of business premise telephony equipment such as the ISDN phone  109 , POTS phone  108 , and VAPs  103 A and  103 B. The Lucent SLC- 2000  (pronounced “Slick”  2000 ) and the Nortel Access Node are exemplary RDTs. The RDT  102  interfaces digitally with the central office (CO), using, for example a TR-08 or GR-303 trunk configuration, connected with the LDS  104  such as a Lucent 5ESS or a Nortel DMS-1000. The RDT  102  provides the distribution of service interfaces between the LDS  104  and the customer premises, thereby extending the digital access network. 
     The exemplary NSP  106  provides control functionality for VAP  103 A and  103 B, which includes mobile station and mobility management, call control such as handoff, wired and wireless interworking such as DN and MIN mapping, signaling processing interface and management, AIN for call processing, service creation and management and feature applications, along with related OAM&amp;P functions. The NSP  106  is also responsible for Network Intelligence and resource management including RF management (e.g., SC), validation or authentication, registration, and Message Center operation and control. 
     An illustrative NSP is described in co-pending U.S. patent application Ser. No. 09/100,360 entitled “Hybrid Fiber Twisted Pair Local Loop Network Service Architecture” by Gerszberg et al., which is herein incorporated by reference. While the NSP described by Gerszberg et al. is not for a wireless centrex system, it can be modified to work in the WCS of the present invention. In the WCS environment, the NSP  106  may include NSP specific software operating on a high performance, general purpose computer, for example, a SUN SPARC Enterprise server E3500. 
     The exemplary Voice Access Ports (VAPs)  103 A and  103 B are pico-cellular intelligent base stations or radio transceiver ports that support, for example, the IS-136 air interface with IS-136 mobile stations such as digital TDMA cellular/PCS communications units  101   a,    101   b.  IS-136 is the EIA/TIA Interim Standard that addresses digital cellular and PCS (personal communications services) systems employing time division multiple access (TDMA). IS-136 specifies a DCCH (Digital Control Channel) to support new features controlled by a signaling and control channel between a cell site (e.g., radio base station) and terminal equipment (e.g., mobile station). The IS-136 air interface between the VAPs  103   a,    103   b  and mobile stations MS  101   a,  MS  101   b  can support voice and messaging applications. The mobile stations MS  101   a,  MS  101   b,  etc., may be, but are not limited to, a terminal or a typical cellular/mobile phone having a keypad, display screen, and an alarm generator for generating a ringing or tone sound. 
     The VAPs support plug-and-play operations by connecting to RDT  102  via standard open interfaces, such as ISDN BRI. In one embodiment, the VAPs  103 A and  103 B use advanced digital software radio technology for superior RF performance. Additionally, VAPs  103 A and  103 B may employ self configuration algorithms for “stacked spectrum” operations. U.S. Pat. Nos. 5,809,423, 5,787,352, 5,740,536, 5,404,574, and 5,345,499 describe exemplary algorithms and related methodologies that may be utilized in self configuration for “stacked spectrum” applications. The VAPs also administer resource management. 
     The mobile stations (MS)  101 A and  101 B provide the WCS subscriber with cordless-like services feature/function, thereby permitting user mobility within the WCS service coverage area. The IS-136 digital TDMA cellular/PCS mobile stations  101 A and  101 B, may include, for example the Nokia 2160 and the Ericsson DH368 TDMA digital telephones. One significant advantage of the instant invention is that a base station may be interconnected to a switch via an open standard interface, such as ISDN BRI, so that traditional wireline services, such as centrex type services features/functions like call hold, call forward, call waiting, call transfer, speed calling, caller ID, three party (conference) calling, etc., may be offered to MS  101 . 
     In one exemplary embodiment of the WCS, there are five major interfaces as illustrated in FIG.  1 . With reference to FIG. 1, interface  1 , connects the LDS  104  to the RDT  102  using, for example, the Bellcore standard GR303 interface. The GR303 standard defines digital transmission facility interfaces such as DS1 and SONET, concentration options between the integrated digital terminal/switch (IDT)  105  and the RDT  102 , signaling options, and call processing and operations data links. The transport media for this interface can be, for example, metallic or fiber-optic. Exemplary metallic media include T1, ISDN/PRI and DS3, while exemplary fiber-optic media include SONET OC3 and OC12 links. Interface  1  carries the voice traffic of a telephone call, as well as the signaling traffic for the LDS  104  and the NSP  106 . 
     Interface  2 , connects the VAPs  103 A and  103 B to the RDT  102  with, for example, ISDN/BRI lines (2B+D channels), using the Q.931 signaling protocol on the D-channel to setup the voice connection on the B-channel. In this case, the RDT acts only as a transport for the signaling and data message to the LDS  104 . WCS call processing messages for call setup, call teardown, feature applications on the RF (IS-136) and OAM&amp;P messages are carried over X.25 packet, interface  4 , on the D-channel between the NSP  106  and the VAPs  103 A and  103 B, via the LDS  104  and the RDT  102 . These messages are sent to the LDS  104 , which routes them to the NSP  106 . Voice connections between the VAPs  103 A and  103 B and the LDS  104  are carried on the B-channel via the RDT  102 . Additionally, software downloads from the NSP  106  are also carried on the D-channel or B-channel to the VAPs  103 A and  103 B via the LDS  104  and the RDT  102 . In one exemplary embodiment, the RDT  102  acts as a concentrator and its operation is transparent to the operation the WCS. 
     Interface  3 , may be, for example, an IS-136 air interface between the VAPs  103 A and  103 B and the MSs  101 A and  101 B supporting voice and messaging applications. Interface  4  is, for example, an X.25 protocol link between the NSP  106  and the LDS  104 . Call control and OAM&amp;P messages between the NSP  106  and the VAPs  103 A and  103   b  are carried on the D-channel of interface  2  through interface  1 , through the LDS  104  , and over this X.25 link. 
     Interface  5  may be, for example, an SS7 link connecting the NSP  106  and the LDS  104 . This exemplary interface carries AIN messages which are generated by the LDS  104 , sent to the NSP  106  for processing, and sent back to the LDS  104  to instruct the LDS  104  how to route the call properly. Interface  5  carries AIN messages from the LDS  104  which notify the NSP  106  of AIN trigger events. It also carries responses from the NSP  106  to the LDS  104  which instructs the LDS  104  how to properly route calls to the WCS subscribers. 
     When the IS-136 cellular/PCS mobile stations  101 A and  101 B are located within the WCS system coverage area, MIN-based calls to the public cellular network destined for mobile stations  101 A and  101 B may not be delivered in the WCS service area. Instead, the IS-136 phones can be associated with the DN of a stationary phone (e.g., POTS  108  or ISDN  109 ) within the WCS services area so that the LDS  104  delivers the call to either the subscriber&#39;s MS  101  or the subscriber&#39;s stationary phone using the DN. On the other hand, when the subscriber&#39;s mobile station MS  101  is located outside the WCS service area, calls are delivered to the mobile stations through the MIN provided in the public cellular system. 
     After a simple registration process, the WCS subscribers use their IS-136 digital TDMA cellular/PCS phone  101 A or  101 B as a cordless-like telephone within the wireless centrex service area without incurring air-time charges. Typically, when an incoming call destined for a WCS subscriber&#39;s DN reaches the LDS  104 , and the DN was previously provisioned for AIN treatment, an AIN trigger occurs in the LDS and an AIN query message is sent to the NSP  106 . In one embodiment, each WCS subscriber has a reachable desktop DN and each DN will be programmed for the AIN trigger in the LDS  104  for call routing purposes. The NSP  106  provides appropriate routing instructions to the LDS  104  for delivery of the incoming call. The NSP  106  can locate and alert the subscriber&#39;s mobile station and direct the LDS  104  to route the incoming call to the mobile station (MS  101 ). If the subscriber does not answer, the NSP  106  may direct the LDS  104  to route the incoming call to a Voice Message System (VMS)  107 , which ultimately answers the call. An exemplary VMS is the Lucent Conversant Model MAP/100C (MultiAccess Platform). Calls initiated from a stationary phone such as POTS  108  or ISDN  109 , or mobile station  101  within the WCS service area are sent to the LDS  104  that can handle the call or route the call to the PSTN  125 . 
     The WCS is a self-configurable indoor wireless system that applies the “stacked spectrum” concept. It can detect (sniff) and designate unused and interference-free DTC/DCCH (Digital Traffic Channel/Digital Control Channel) from the overlayed (e.g., macro or micro) cellular system, for its own use, based on the unique WCS private systems number (PSID). The DTC is defined in IS-136 as the portion of the air interface which carries the actual data transmitted (e.g., the voice channel). It operates over frequencies separate from the DCCH, which are used for signaling and control purposes. Since the WCS coexists with public macro or micro cellular networks, it monitors the RF channel activities, detect unused and interference-free channels, and makes channel selections and adjustments in real time for interference-free operation. 
     Another exemplary network architecture of the WCS is illustrated in FIG.  2 . The WCS system may be installed at the satellite site (e.g., Customer Site B)  201  as well as the main site (e.g., Customer Site A)  202 . When a subscriber is provisioned for service, the Customer Service Center (CSC)  113  downloads the subscriber&#39;s profile to all NSPs  106  (e.g.,  106 A and  106 B). The subscriber is allowed to roam between the customer sites  201  and  202 . In one exemplary embodiment, the NSPs  106 A and  106 B are interconnected through the provider Intranet  112 , for example, AT&amp;T Intranet. However, the NSP&#39;s  106 A and  106 B may be interconnected through any secure virtual network from any provider. 
     In the WCS, a call is delivered by the Local Digital Switch  104 A or  104 B using the DN. Unlike normal wireline phone services, however, the location of the WCS subscriber changes continuously with movement of the MS  101  within the service area. Therefore, a special intelligent delivery mechanism using Advanced Intelligent Network (AIN) has been developed for the WCS call delivery. In the AIN architecture, the Service Switching Point (SSP), here the LDS  104 A and  104 B has the capability of determining which calls require AIN services based on the dialed DN. The process of identifying calls that require AIN processing is known as “triggering,” since a particular characteristic of the call “triggers” the switch into providing AIN call treatment. So, when the DNs of ISDN telephone  109  or POTS telephone  108  are provisioned as WCS DNs, an incoming call to these DNs will prompt an AIN trigger. Once an event causing a trigger occurs, a query message is sent to the Service Control Point (SCP) as illustrated in FIGS. 5,  6  and  7 . The SCP is, for example, NSP  106 . Based on the information contained in the query message, the SCP (NSP  106 A or  106 B) determines which service is being requested and provides appropriate information to the LDSs  104 A or  104 B. In the exemplary WCS architecture, all the routing information is stored in the NSPs  106 A and  106 B. Therefore, the LDSs  104 A and  104 B in the WCS sends the query message to the NSPs  106 A and  106 B, and the NSPs  106 A and  106 B directs the LDS  104 A and  104 B to deliver the call to its appropriate destination. A detailed description of mobile station registration in the WCS follows. 
     III. Mobile Station Registration 
     FIG. 3 shows an exemplary embodiment of a registration process used to register a MS  101  when the MS  101  enters a WCS service region (e.g., customer site B  201 ). Upon entering the WCS system service area, the MS  101  automatically registers with the NSP  106  serving that customer site. The NSPs  106 A and  106 B contain the subscriber profiles distributed by the Customer Service Center  113  (CSC). The NSP ( 204 A or  204 B) handling the call then validates the MS  101  by examining the subscriber profile for that MS  101 . If the subscriber is roaming to another Customer Site, the Serving NSP  106 B notifies the Home NSP  106 A that the subscriber is registered in its (Serving NSP&#39;s  106 B) service area. 
     In particular, when the MS  101  is powered on, an IS-136 Registration message  307  is sent to the VAP  103 . The VAP  103  then forwards the registration notification message  308  to the serving NSP  106 B. The serving NSP  106 B validates the subscriber by looking up the subscriber information stored locally and previously downloaded from the customer service center (CSC)  113 . If the NSP  106  was not the subscriber&#39;s Home NSP  106 A, then a registration notice message REGNOT  309  would be sent to the Home NSP  106 A for the MS  101  indicating that MS  101  was registered now in serving NSP  106 B&#39;s area. The Home NSP  106 A would then store the roaming information of the MS  101 , and send regnot message  310  to the Serving NSP  106 B for acknowledgment. However, with the assumption that the Home NSP  106 A was indeed the actual Home NSP of the MS  101 , then the Home NSP  106 A sends a regnot message  310  to Serving NSP  106 B. If the Home NSP  106 A found that the MS  101  had been registered at another NSP, e.g., Old NSP  106 C, and had left without proper de-registration, then the Home NSP  106 A would send a registration cancellation message REGCANC,  311 , to cancel the previous registration at the Old NSP  106 C for confirmation. The Old NSP  106 C would then remove the records for the MS  101  from its memory, and send a registration cancellation response message, regcanc,  312 , back to the Home NSP  106 A. However, assuming that Home NSP  106 A had sent the regnot  310  message to Serving NSP  106 B, then Serving NSP  106 B would send a registration acceptance message, Registration Accept,  313 , to VAP  103 . The VAP  103  then informs MS  101  that the registration is completed, by sending IS-136 registration acceptance message, Registration Accept  314 , to MS  101 . This completes the registration process for MS  101 . Registration in the MS  101  Home NSP  106 A is simpler requiring only steps a and d illustrated in FIG.  3 . 
     IV. Call Origination From A Mobile Station 
     FIG. 4 shows an exemplary call origination from a MS  101  directed to a PSTN  125  DN. When the subscriber MS  101  places a call via an origination message, IS-136 Origination  407 , the VAP  103  first checks the validity of the MS  101  with NSP  106  via Origination Request  408 . The NSP  106  then provides the VAP  103  with an Origination ACK  409  message indicating that the MS  101  is recognized and the VAP  103  may go forward with the call origination. After that, the VAP  106  sets up an ISDN connection, ISDN Set up  410 , to LDS  104 . The LDS  104  performs the dialed digit analysis and proceeds with the call delivery procedures concluding in a connected call to the PSTN  125  DN. 
     More specifically, the MS  101  dials a DN number and sends an IS-136 Origination  407  message to VAP  103 . VAP  103  then sends an Origination Request  408  message to NSP  106 . After checking the appropriate databases to determine if the MS  101  is a valid registered subscriber, NSP  106  returns an Origination ACK  409  message to VAP  103 . The VAP  103  then reserves a RF DTC channel and sends an ISDN Q.931 Setup  410  message to the LDS  104 . The LDS  104  then performs a dialed digit analysis and sends an ISUP IAM  411  message to a far end switch in the PSTN  125  for end-to-end connectivity. The LDS  104  also sends an ISDN (Q.931) Call Proceeding  412  message to the VAP  103 . The VAP  103  then sends an IS-136 Digital Traffic Channel (DTC) Designation  413  message to the MS  101  so that MS  101  may then tune to the designated traffic channel. MS  101  indicates to VAP  103  that it is using the designated DTC by responding with an MS on DTC  414  message. The VAP  103  then detecting that the MS  101  is tuned to the designated traffic channel, cuts through the voice path between RF DTC channel and ISDN B channel. 
     After receiving the ISUP ACM  415  message from the destination switch in the PSTN  125 , the LDS  104  sends an ISDN Alerting  416  message to VAP  103 . Next, the Ringback Tone  421  is delivered to the MS  101  from the destination switch. When receiving ISUP ANM  417  message from the PSTN  125 , the LDS  104  sends an ISDN Connect  418  message to VAP  103 , removes the ringback tone, and cuts through voice path  422 . The VAP  103  then sends an ISDN Connect ACK  419  message back to the LDS  104 . After connection of the voice path  422 , the VAP  103  sends a Connected  420  message to the NSP  106  for billing and other OAM&amp;P purposes. 
     V. Incoming Call Termination 
     Exemplary call flow diagrams illustrating various call termination (incoming call connection) scenarios for the WCS system are illustrated in FIGS. 5 through 7. When provisioning the necessary parameters for the subscriber, the WCS subscriber&#39;s DN is provisioned for the AIN Termination Attempt Trigger (TAT) so that the subscriber&#39;s mobile station is the first destination determined for incoming call termination. Consequently, when a call to the subscriber&#39;s DN is received, it triggers the LDS  104  to send a call treatment query message to the NSP  106 . The TAT call treatment procedure in the NSP  106  will direct the LDS  104  to deliver the call to its appropriate destination. The DN in the VAP  103  that is used to deliver the call to the MS  101  is referred to as the Forward Directory Number (FDN). 
     Depending on the first call delivery destination, there may be two different call termination scenarios. The first scenario involves delivering the call first to a tip ring (T/R) desktop phone  108  (POTs) or an ISDN phone  109 , while the second involves delivering a call first to a mobile station  101 . In each scenario, a different AIN trigger is utilized, and the call termination may be implemented using one of the two scenarios. The latter scenario of delivering the call to a mobile station will be utilized to exemplify the procedure. 
     The TAT call treatment procedure in the NSP  106  will direct the LDS  104  to deliver the call to the subscriber MS&#39;s current location. If there is no answer from the MS  101  phone, the call is delivered to the subscriber&#39;s desktop phone (e.g., POTs  108  or ISDN  109 ). In one exemplary embodiment, once the call is forwarded to the MS  101  DN (FDN), the call follows the Originating Call Model (OCM) rather than the Terminating Call Model (TCM), and an O_No_Answer trigger can be used rather than a T_No_Answer trigger. In yet another embodiment, the T_No_Answer trigger could be used to deliver the call to the desk top phone first, and if the call goes unanswered, the trigger can be used to request additional routing information from the NSP  106 . The NSP  106  would then locate the MS  101  and instruct the LDS  104  how to deliver the call. 
     An exemplary call flow of a termination wherein the incoming call is routed from the PSTN  125  to MS  101  is illustrated in FIG.  5 . As previously illustrated in FIG. 4, if the call is originated from the MS  101  or desktop phone (e.g.,  108  or  109 ) inside a region handled by the same LDS  104 , the resulting call flow would be similar, except that there will be appropriate ISDN Q.931 messages to and from the LDS  104  instead of the ISUP messages between the PSTN  125  and the LDS  104 . The following illustration shows an incoming call to a MS  101  that answers the call. 
     The PSTN  125  user first dials the DN of a WCS subscriber. The LDS  104  then receives an ISUP IAM  508  message from the PSTN  125 . The LDS  104  recognizes that the DN is provisioned for AIN Termination Attempt Trigger (TAT). The LDS  104  then suspends the delivery of the call and sends an AIN query message, TCAP (AIN termination attempt [DN])  509 , to the NSP  106  for an appropriate routing instruction. The NSP  106  recognizes that the subscriber&#39;s MS  101  is active in its serving area, and sends a page message, Page  510 , to the VAP  103  serving MS  101 . The VAP  103  in turn sends an IS-136 Page  528  message to the MS  101 . The MS  101  responds to the IS-136 Page  528  via a IS-136 Page Response  529  message destined to VAP  103 . VAP  103  then sends a Page Response  511  message to the NSP  106 . The NSP  106  then directs LDS  104  to forward the call to the Forward Directory Number (FDN), TCAP (AIN Forward_Call [FDN], NEL [O_No_Answer])  512  of the VAP  103  serving the MS  101  (in a TCAP Conversation package). The NSP  106  also indicates its interest in event (O_No_Answer for FDN) by sending next event list NEL [O_No_Answer])  532  information to the LDS  104  in a Request component that accompanies the Routing component, in a conversation package. The LDS  104  then starts a No Answer Timer (T(NoAnswer))  531  for FDN and sends an ISDN (Q.931) Setup  513  message to the VAP  103 . The VAP  103  then sends a Digital Traffic Channel (DTC) Designation  530  message to the MS  101  along with an ISDN (Q.931) Call Proceeding  514  message to the LDS  104 . The MS  101  then tunes to the traffic channel and responds to the VAP  103  with MS  101  on DTC  515 . The VAP  103  detects that the MS  101  is on the appropriate traffic channel. The VAP  103  then alerts MS  101  with an Alert-with-info  516  message and MS  101  acknowledges with a Mobile ACK  517  message. The VAP  103  then sends an ISDN Alerting  518  message to LDS  104 . 
     Upon receiving ISDN (Q.931) Alerting  518  message, the LDS  104  then sends an ISUP ACM message  519  to the switch in PSTN  125 . In the meantime, the LDS  104  is sending a nngback tone  520  to the PSTN  125  caller. When the MS  101  answers (before T(No Answer)  531  expires), the VAP  103  sends an ISDN Connect message  522  to the LDS  104  in response to the Connect  521  message from MS  101 . The LDS  104  then cancels T(No Answer)  531 , and sends ISUP ANM  523  message to the PSTN  125  switch and cuts through the voice path  527 . After the LDS  104  sends an ISDN (Q.931) Connect ACK  524  message to the VAP  103 , it then sends TCAP (AIN Close)  525  message to the NSP  106  (using TCAP Response) to complete the TCAP transaction. After receiving the ISDN (Q.931) Connect ACK message  524  from the LDS  104 , the VAP  103  sends Connected  526  message to the NSP  106  for billing and other OAM&amp;P purposes. At this point, voice path  527  has been established and the call proceeds between the PSTN  125  caller and the MS  101  subscriber until it is ended and disconnected (e.g., hang up). 
     In accordance with the instant invention, FIG. 6 shows a process wherein an incoming call goes unanswered by the mobile station, e.g., MS  101 , and the No Answer Timer  531  expires. Whenever, a call destined for a MS  101  goes unanswered and the No Answer Timer  531  expires, the NSP  106  will direct the call to the DN (telephone or VMS) which is associated with that MS  101 . 
     The PSTN  125  user first dials the DN of a WCS subscriber. The LDS  104  receives ISUP IAM  508  message from the PSTN  125 . The LDS  104  will recognize that the DN is associated with MS  101  and is provisioned for AIN Termination Attempt Trigger (TAT). The LDS  104  then suspends the delivery of the call and sends an AIN query message, TCAP (AIN Termination Attempt [DN]  509 ), to NSP  106  for an appropriate routing instruction. The NSP  106  will recognize that the subscriber&#39;s MS  101  is active in its serving area, and will send Page  510  message to the VAP  103  serving MS  101 . The VAP  103  in turns sends IS-136 Page  528  message to MS  101 . The MS  101  will respond to the IS-136 Page  528  message via Page Response  529  message destined to VAP  103 . The VAP  103  then sends Page Response  511  message to the NSP  106 . The NSP  106  then directs the LDS  104  to forward the call to the Forward Directory Number (FDN) of the VAP  103  serving the MS  101  (in a TCAP Conversation package) by sending the TCAP (AIN Forward Call [FDN], NEL [O_No_Answer])  512  message to the LDS  104 . The NSP  106  also indicates its interest in event O_No_Answer for FDN by sending next event list (NEL) information to the LDS  104  in a Request component accompanying the Routing component of a conversation package message  512 . The LDS  104  then starts a No Answer Timer (T(NoAnswer))  531  for FDN and sends ISDN (Q.931) Setup  513  message to the VAP  103 . The VAP  103  then sends Digital Traffic Channel (DTC) Designation  530  message to MS  101  and sends a ISDN (Q.931) Call Proceeding  514  message to the LDS  104 . The MS  101  then tunes to the designated traffic channel and sends the MS  101  on DTC  515  message to VAP  103 . The VAP  103  then detects the MS  101  on the traffic channel and alerts the MS  101  with an IS-136 Alert-with-info  516  message the MS  101  responds by acknowledging with a Mobile ACK  517  message. The VAP  103  then sends ISDN Alerting  518  message to the LDS  104 . Upon receiving the ISDN (Q.931) Alerting  518  message, the LDS  104  then sends an ISUP ACM  519  message to the switch in PSTN  125 . In the meantime, the LDS  104  is sending a ringback tone  520  to the caller. 
     In this case, the MS  101  does not answer the call and the No Answer Timer T (No Answer)  531  expires. The LDS  104  then sends AIN O_No_Answer  625  message to the NSP  106  in a conversation package. The NSP  106  sends a TCAP (AIN Analyze_Route [DN])  626  message to the LDS  104 . Then the LDS  104  sends a TCAP (AIN Termination_Attempt [DN])  635  message back to the NSP  106 , which authorizes the call termination to the DN by sending an TCAP (AIN Authorize_Term)  636  message to the LDS  104 . The LDS  104  then sends an ISDN (Q.931) Disconnect  627  message to the VAP  103 . The VAP  103  then sends a Release  628  command to the MS  101  and the MS  101  stops ringing (buzzing or alert the user). The MS  101  then sends Mobile ACK  629  back to the VAP  103 . The VAP  103  now sends ISDN (Q.931) Release  630  message to LDS  104  to notify the LDS that MS  101  is no longer being alerted of the incoming call. The LDS  104  then sends ISDN (Q.931) Release Complete  631  message to the VAP  103  allowing MS  101  to be used for other calls or messages. When the NSP  106  instructs the LDS  104  to forward the call to the DN  626 , the call processing is assumed by the LDS  104  as a normal call delivery in step  632 . If the user subscribes to VMS  107 , then after a certain number of rings, the LDS  104  will transfer the call to the VMS  107 . The incoming call will thus be forwarded to the telephone (ISDN  109  or POTS  108 ) associated with the DN being called. 
     In accordance with the instant invention, an exemplary methodology of terminating an incoming call to a roaming subscriber located in another LDS area is illustrated in FIG.  7 . The WCS subscriber&#39;s DN is provisioned for the AIN Termination Attempt Trigger (TAT) so as to seek out the subscriber&#39;s MS first. In general, when a call to the subscriber&#39;s DN arrives at the LDS  104 , the call triggers the LDS  104  to send a call treatment query message to NSP  106 . The NSP  106  will recognize that the MS  101  is currently registered in another Customer Site (different LDS area) and will request a Forward Directory Number (FDN) from the visited area, Serving NSP  106 B. The Serving NSP  106 B then checks the current location of the MS  101  and the availability of circuits to handle the call and returns an FDN to the Home NSP  106 A. After receiving the FDN, the TAT call treatment procedure in the Home NSP  106 A directs the LDS  104 A to deliver the call to the FDN. After sending the ISUP IAM to the FDN, the Serving LDS  104 B delivers the call to the VAP  103  presently serving the MS  101 . 
     More particularly, a call termination occurs as follows when a MS  101  is roaming to another Customer Site, e.g., Site B  201 , when the MS  101  has a home location within Customer Site A  202 . The PSTN  125  user dials a WCS subscriber&#39;s DN associated with a subscriber in Customer Site A. The Home LDS  104 A (LDS-A) receives an ISUP IAM  709  message from the PSTN  125 . The LDS-A  104 A finds that the DN is provisioned for AIN Termination Attempt Trigger (TAT) and suspends the delivery of the call, sending AIN Term ination_Attempt Query  710  message to the NSP-A  106 A for an appropriate routing instruction. The NSP-A  106 A will recognize that the subscriber is not presently registered in its serving area but is now registered in Customer Site B  201 . The NSP-A  106 A will send ROUTREQ  711  message to the Serving NSP (NSP-B)  106 B. After receiving the ROUTREQ  711  message, the NSP-B  106 B sends Page  712  message to the VAP  103  presently serving the MS  101 . The VAP  103  will then send an IS-136 Page  713  message to the MS  101  and the MS  101  will respond with an IS-136 Page Response  714  message destined for the VAP  103 . The VAP  103  will then send the Page Response  715  message to the NSP-B  106 B. The NSP-B  106 B will confirm the current location of the MS  101 , and return the Forward Directory Number (FDN), in the routreq  716  message to the NSP-A  106 A. The NSP-A  106 A will then direct the LDS-A  104 A to forward the call to FDN in Customer Site B via a TCAP (AIN Forward_Call [FDN], NEL[O_No_Answer])  717  message. The LDS-A  106 A then forwards an ISUP IAM [FDN]  718  message to the LDS-B  104 B. After receiving the ISUP IAM [FDN]  718  message, LDS-B  104 B then sends an ISDN (Q.931) Setup  719  message to the VAP  103  serving the FDN. VAP  103  sends the DTC Designation  720  message to the MS  101 , and then sends an ISDN (Q.931) Call Proceeding  721  message to the LDS-B  104 B. When the MS  101  tunes to the DTC it sends an MS on DTC  722  message to VAP  103  and VAP  103  responds with an Alert-with-info  723  message. The MS  101  will then send a Mobile ACK  724  message to the VAP  103  and the VAP  103  will then send an ISDN (Q.931) Alerting  725  message to the LDS-B  104 B. The LDS-B  104 B will then send an ISUP ACM  726  message to the LDS-A  104 A, which will in turn forward a ISUP ACM  727  message to the switch in PSTN  125 . The LDS-B  104 B provides the Ringback Tone  728  to the caller. 
     When the MS  101  answers, the MS  101  will send Connect  729  message to the VAP  103 . The VAP  103  will then send an ISDN (Q.931) Connect  730  message to the LDS-B  104 B. The LDS-B  104 B will then send an ISUP ANM  731  message to the LDS-A  104 A, which then forwards ISUP ANM  733  to the switch in PSTN  125 , and an ISDN Connect ACK  732  message to VAP  103 . After receiving an ISDN (Q.931) Connect ACK  732  message from LDS-B  104 B, the VAP  103  will send a Connected  734  message to the NSP-B  106 B for billing and other OAM&amp;P purposes. 
     If the MS does not answer, the call is delivered to the desktop phone or to the VMS  107  if the MS  101  subscriber has voice mail capabilities, by the same mechanism using the NEL [O_No_Answer], as in the non-roaming case (see FIG.  6 ). Otherwise, at this point, voice path  735  is established. 
     VI. Intra-LDS Mobile Station Assisted Handoff 
     In accordance with the invention, an exemplary embodiment of an intra-LDS mobile assisted handoff (MAHO) process is illustrated in FIG.  8 . The signaling flow in FIG. 8 discloses the handoff of a call between the VAPs (e.g., VAPo  103 A and VAPn 103 B) served by the same LDS  104 . The smooth/lossless handoff is accomplished by using the Directed Call Pickup with Barge-in (DPU) feature supported by many switches. A discussion of the process follows. 
     While a call  806  involving the served MS  101  is in progress, the VAPo  103 A detects a handoff condition based on the measured channel qualities and their threshold value. The VAPo  103 A initiates a Measurement order  807  destined for MS  101 . The MS  101  then responds to the Measurement order  807  with a Measurement order ACK  808  and a Channel Quality Message  809  destined for VAPo  103 A. When VAPo  103 A detects a handoff condition, it then sends a Handoff Request  810  to the NSP  106  with a list of candidate channels. The NSP  106  then selects the best candidate channel, identifies VAPn  103 B as serving the channel, and sends a Handoff Preparation [MSID, DN-VAPo]  811  message to VAPn  103 B. 
     Upon receiving the order from NSP  106 , VAPn  103 B reserves a B-channel and a RF channel for the MS  101 , and establishes a 3-way call using the DPU feature. VAPn  103 B then sends ISDN (Q.931) Setup [Feature Activation (DPU), DN-VAPo]  812  message to LDS  104 . LDS  104  then returns an ISDN (Q.931) Call Proceeding  813  message to the VAPn  103 B, followed by an ISDN (Q.931) Connect  814  message. The VAPn  103 B then responds to the LDS  104  with an ISDN (Q.931) Connect ACK  815  message. The VAPn  103 B then sends a Handoff Directive  816  message to VAPo  103 A. The VAPo  103 A then sends the Handoff order  817  to the MS  101  requesting MS  101  to retune to the new RF channel of VAPn  103 B, and disconnects its ISDN connection to the LDS  104  as shown in steps  818 - 823 . The MS  101  is then placed on the new channel with VAPn  103 B per step  824 . The VAPn  103 B sends a message Handoff Result  825 , to the NSP  106 , which indicates that the MS  101  has successfully been handed off to the new channel, indicated as handoff complete. 
     In yet another embodiment of the invention, a user on a wireline telephone call can have the capability of transferring that call to his/her cellular/PCS MS. In accordance with this feature, a user on a wireline telephone with an active call may enter a special feature code, such as *99, in order to activate the feature. 
     The following is a more detailed description of an exemplary intra-LDS mobile assisted handoff as previously described and as depicted in FIG.  8 . Initially, there is an existing call involving the served MS  101  in progress. The VAPo  103 A sends a Measurement order  807  over the FACCH to the MS  101  to measure the BER (bit error rate) and RSSI (received signal/strength indicator) of the-current channel and the RSSIs of other RF channels. The MS  101  acknowledges the Measurement order  807  by sending a Measurement order ACK  808  over the FACCH. The MS  101  then performs the channel quality measurements in response to the Measurement order  807  and sends a Channel Quality message  809  to the VAPo  103 A. 
     Next, the VAPo  103 A detects a handoff condition based on the received Channel Quality Message  809  and the associated threshold values. The VAPo  103 A then sends a Handoff Request  810  message to NSP  106  with a list of candidate channels, and immediately starts its handoff request timer (T 1 ). Upon receiving the Handoff Request  810  from the VAPo  103 A, the NSP  106  selects the candidate with the strongest RSSI. The NSP  106  then checks if the resources (ISDN B-channel and RF channel) are available for the candidate channel, and identifies VAPn  103 B as the new VAP which will serve the MS  101 . The NSP  106  then sends a Handoff Preparation  811  message, including the serving MSID and DN-VAPo (the DN of VAPo  103 A, i.e., the phone number to be barged in on) to VAPn  103 B and immediately starts its handoff preparation timer (T 2 ). In response to the Handoff Preparation  811  message, VAPn  103 B then reserves a B-channel and a RF channel for the MS  101  and starts to establish a 3-way call using a DPU process in the following manner. 
     The VAPn  103 B sends a ISDN (Q.931) Setup  812  message to LDS  104 , which includes a Feature Activation code for DPU and DN-VAPo. The LDS  104  then sends the ISDN (Q.931) Call Proceeding  813  message back to the VAPn  103 B followed by an ISDN (Q.931) Connect  814  message when the call is connected to DN-VAPo. The VAPn  103 B then sends the ISDN (Q.931) Connect ACK  815  message to LDS  104 . The VAPn  103 B then sends a Handoff Directive message  816  to the VAPo  103 A. The VAPo  103 A cancels the T 1  timer, and sends the Handoff order  817  to the served MS  101  over the FACCH, requesting the MS  101  to retune to the new RF channel (along with other channel assignment information). The MS  101  then acknowledges the Handoff order with a Handoff ACK  818  to VAPo  103 A. Upon receiving the Handoff ACK  818 , the VAPo  103 A then disconnects the B channel connection by sending an ISDN (Q.931) Disconnect  819  message to LDS  104 . LDS  104  then sends an ISDN (Q.931) Release  820  message to the VAPo  103 A, and the VAPo  103 A acknowledges the Release Message  820  and disconnection of the previous call by sending the ISDN (Q.931) Release Complete message  821  to the LDS  104 . The VAPo  103 A tears down the voice path connection that it had established for the MS  101 . The VAPo  103 A sends the Handoff Complete  822  message to the NSP  106 , which includes the time information of the serving MS  101  for billing and other OA&amp;M purposes. The LDS  104  then starts its handoff complete timer (T 3 ). The NSP  106  responds by sending a Handoff Complete ACK  823  to VAPo  103 A, and VAPo  103 A cancels T 3 . The MS  101  then retunes to the new channel of the VAPn  103 B. After confirming that the MS  101  has been retuned to the new channel, the VAPn  103 B then sends a Handoff Result  825  message to the NSP  106 , which indicates that the MS  101  has been successfully handed off to a new channel and timer T 2  is cancelled. The NSP  106  acknowledges the handoff complete to both the LDS  104  and the VAPn  103 A, using handoff complete  826  message. 
     VII. WCS As A Wireless PBX System 
     In yet another embodiment of the instant invention, there exists a wireless centrex service platform which is a Wireless PBX system (WPS) offering a wireless access system with customer site wireline ISDN capable PBX to provide integrated wire and wireless voice access. In one application of the system, a WPS as disclosed could be used to enhance the PrimeXpress service offered Teleport Communications Group (TCG, now owned by AT&amp;T). This system could advantageously provide a cordless-like, anywhere, anytime communication in any indoor, business and campus environment using subscriber&#39;s macrocellular/PCS mobile station (MS  101 ). In accordance with the invention, the WPS system includes an Intelligent Wireless Controller (IWC) system  902 , its subtending Voice Access Ports (VAPs)  103  and the customer site ISDN capable PBX  901 . 
     Additionally, the WPS also functions as an integrated wireline and wireless system without being connected to any public macro cellular system. Therefore, it does not support mobility management and roaming between WPS and the public macro cellular and PCS networks. In another embodiment, the WCS can connect the NSP  106  to a macrocellular SS7 network to support integrated mobility functions including terminal handoff and personal roaming features. 
     Further, the WPS provides location and mobility management for the WPS subscriber&#39;s mobile station (MS  101 ) inside the WPS serving area. 
     After a simple registration process, the WPS subscribers use their IS-136 digital TDMA cellular/PCS phone  101  as a cordless-like phone in the WPS service area without incurring air-time charges. The dual ring feature of the MS  101  allows the user to receive calls anywhere inside the WPS service area. As a result, whenever a user is called at his/her stationary phone  108  attached to the customer premises PBX  901 , the WPS system simultaneously locates and alerts the user&#39;s IS-136 phone  101 . If the user does not answer MS  101 , the Voice Message System  109  associated with the customer premises PBX  901  will answer the call. In this embodiment, calls from the stationary phone  108  or the IS-136 phone  101  are directed to the customer site PBX and processed by the TCG PrimeXpress Services. Essentially, the PrimeXpress service is an outbound trunk to a switch  904 , such as the Lucent 4ESS, that bypasses the local switch. In the exemplary WPS system, call features include, but are not limited to, Short Message Services (SMS) and/or paging (IS-136 feature); PBX interworking, including premises dialing plan, closed-user-group, and dual ringing of stationary and MS phones; wireline call features, such as three way calling, call forwarding, call transfer, caller ID, call waiting, messaging and voice mail services; support for voice privacy; and cordless-like service without air time charges. 
     In the embodiment of the invention illustrated in FIG. 9, there exists an ISDN PRI interface  7 , an IS-136 air interface  3 , and an ISDN BRI interface  2 . The ISDN BRI  2  interconnects VAP  103  and the Intelligent Wireless Controller  902 . Call processing messages for call setup, call teardown, feature applications and OAM&amp;P messages are carried on the data D-channel in X.25 packets. In addition to carrying call processing messages, the D-channel also carries ISDN (Q.931) signaling for call setup and teardown of the voice connection on the bearer B-channel. The IS-136 air interface  3 , provides communication between the VAP  103  and the MS  101 . The ISDN PRI interface  7  interconnects the IWC  902  and the customer premise PBX  901  and utilizes Q.931 signaling. The wireless communications controller&#39;s call processing messages for call setup, call teardown, feature applications and OAM&amp;P messages are carried in the D-channel to the NSP  106 . The D-channel also carries the Q.931 messages for the voice connections on the B-channels between the VAP  103  and the IWC  902 . In one embodiment of the Intelligent Wireless Controller (IWC), there exists an ISDN switch  903  and a controller circuit. 
     VIII. Wireless Voice and Data WCS 
     In yet another embodiment of the instant invention, there is a Wireless Communication Service Platform that offers an economical and high performance wireless access network, for satisfying the need for an in-building integrated voice and data system providing mobility. While the exemplary platforms previously disclosed are focused on providing voice capabilities, this embodiment discloses a platform for providing data support integrated with voice capability. There exist at least one Data Access Port (DAP) (e.g., DAP  1001 A or DAP  1001 B), which is a micro-cellular base station that uses the CelluLAN™ Common Air Interface (IEEE802.11) for high density and seamless in-door coverage providing 4 to 10 Mbps data rate for data applications. 
     The architecture of the DAP is similar to that previously disclosed for the VAP, and uses digital software radio technology which provides superior RF performance, along with RF based self configuration algorithms for “stacked spectrum” operation. A 10BaseT or 100BaseT Local Area Network (LAN)  1007  connects the DAPs, as well as other LAN devices such as servers, and or local printers, to the Integrated Wireless Communication Controller  1002  (e.g., Integrated Enterprise Wireless Communication (EWC) Controller). In one exemplary embodiment of the Integrated Wireless Communication Controller, the wireless voice and data services are integrated by bundling the PSTN/voice traffic on a trunk  7  to the LDS  104 , e.g., 5ESS, and switching the data traffic to an ATM network  1005  for internet/intranet access (ISP  1006 ). The data and voice could be switched by any suitable means commonly known in the art such as packet switching or circuit switching. A laptop  1003 A or  1003 B with a PCMCIA card that supports CelluLAN™ CAI, can access the LAN  1007  anywhere inside the building. After the laptop  1003 A or  1003 B has registered with the LAN  1007 , the user can access other PCs, laptops, and or other servers on the LAN, the intranet, and the internet. The user can access this LAN in his office, meeting rooms, the cafeteria, or any area of the building covered by DAPs. Once implemented, the instant invention would provide the advantage of eliminating the need to wire an individual office for data and/or voice connectivity. The wireless communication service platform would potentially improve overall productivity by giving the users access to their desktop anywhere, anytime. In other words, the instant invention would provide a “desktop to go” environment that would support “moment of value communications” at the time needed when information is most critical. 
     In accordance with the invention, there exists a Data Access Ports (DAPs)  1001 A and  1001 B interconnected to an Integrated Wireless Controller  1002 , via interface  8 . Interface  8  is a standard 10/100 BaseT Ethernet connection. This is advantageous in that it provides a flexible interface so that data can be routed via the ethernet interface to a wired LAN or through an ATM network interface  10  to an ATM network  1005  interconnected to an Internet Service Provider (ISP)  1006 . The IEEE 802.11 air interface  9  provides a wireless access to the DAPs  1001 A and  1001 B. The Data Access Port has exemplary capabilities such as, a high speed LAN access from 4-10 Mbps data rate using the CelluLAN™ CAI; an IP address assignment during registration; seamless mobility management including roaming and intra/inter LAN handoffs; data privacy functions to support standard security algorithms; communication support between DAPs and VAPs for SMS, email, paging, and data; and SNMP for OA&amp;M. 
     The exemplary Integrated Wireless Communications Controller  1002  is a single platform controller with Premises Interfaces providing ISDN BRI interfaces  2  and Ethernet interfaces  8  for the VAP and DAP, respectively, and Network Interfaces providing ISDN PRI  7  and ATM for PSTN and ATM network access  10 , respectively. The exemplary ATM network interface  10  is data only, and the Ethernet interface can also be used to connect to a wired Local Area Network (LAN). In accordance with the invention, there exist an ISDN PRI interface  7 , interconnecting the Integrated Wireless Communications Controller  1002  with a LDS  104 . In accordance with the invention, the LDS  104  interconnects to a RDT  102 , a NSP  106  and to trunks connected to networks such as the AT&amp;T Local and Long Distance Network  110 , the PSTN  125 , and the SS7 network  111 . 
     IX. Feature Activation/Deactivation 
     The present invention includes means for feature/function activation/deactivation which is controlled by user input. The NSP  106  contains a dynamic user profile database stored in a memory (see FIG. 12, memory  1240 ) used to, for example, determine whether a mobile station is authorized to use a particular WCS feature/function and whether the feature/function, if available, is active. 
     FIG. 11 illustrates a general signaling flow applicable for both feature activation and feature deactivation for the features/functions of the present invention that require activation/deactivation when MS  101  is idle (MS  101  camping on DCCH). Although FIG. 11 does not illustrate an RDT  102 , it is understood that an RDT  102  may be included in one embodiment and located between the VAP  103  and the LDS  104 . While an MS  101  registered with an NSP  106  is idle, the MS  101  user may dial the feature activation/deactivation code (e.g., *66, representing an activation code for an automatic callback feature/function) and press, for example, the “send” button on MS  101 . In response, an IS-136 Origination [Feature Code]  1101  message (where the entered number feature activation/deactivation code is entered rather than a called party number) is sent to VAP  103  via the DCCH (over-R-DCCH). An IS-136 Serial Number message  1102  also is sent to VAP  103 . After receiving the message, the VAP  103  sends an Origination Request [Dialed Digit]  1103  message to NSP  106  and starts the TO 1  timer. Alternatively, feature activation can be achieved when the MS  101  is active. For example, during an active call the MS  101  user may merely enter the feature code and the feature will be activated. 
     After receiving the Origination Request [Dialed Digit]  1103  message, the NSP  106  analyzes the dialed digits using, for example, controller  1230  (see FIG.  12 ). If the dialed digits includes a feature activation code, the NSP  106  checks the Wireless Centrex System Database (WCSD) (for example a user mobile station service profile database stored in memory  1240  (see FIG.  12 )), using the Mobile Station Identification (MSID) to determine if MS  101  is authorized for the particular feature requested. If the MS  101  is authorized for the feature requested, feature validation is successful and the NSP  106  activates the feature for the subscriber and stores any associated feature information into the user profile database. The NSP  106  then sends an Origination NACK [Cause, Display]  1104  message with the Cause equal to Feature Activation and the Display information indicating successful feature activation, back to the VAP  103  (e.g., Origination NACK [Feature Activation Successful, Call forwarded to FwdDN]). 
     On the other hand, if the dialed digits are a feature deactivation code, the NSP  106  checks the WCSD to see if that particular feature is active. If the feature is active, the NSP  106  deactivates the feature and removes any associated feature information from the WCSD. The NSP  106  then sends an Origination NACK [Cause, Display]  1104  message with the Cause equals to Feature Deactivation and the Display information indicating a successful feature deactivation, back to the VAP  103 . The NSP  106  generates an Origination NACK message rather than an Origination ACK message because the feature activation request is provided to the NSP  106  in a message (Origination Request  1103 ) that is generally intended for use in originating a telephone call and when a feature activation/deactivation is requested when the MS  101  is idle, no call will be complete since no DN was entered, thus, the response by the NSP  106  with a none acknowledgement message, Origination NACK  1104 . However, the Origination NACK  1104  message does contain information in its Cause and Display fields that is needed to inform the MS  101  user that a feature has been activated or deactivated correctly. 
     In either feature/function activation or feature/function deactivation, the VAP  106  then cancels the TO 1  timer and issues an IS-136 Reorder/Intercept [Display]  1105  message with the Display information over the Paging Channel (PCH) to the MS  101 . The IS-136 Reorder/Intercept [Display]  1105  message is similar to the Origination NACK  1104  message in that it is generally an indication message that a call origination request has been unsuccessful and is used in this case as a vehicle for providing the MS  101  user information regarding the status of their feature activation/deactivation. After receiving the message, MS  101  displays the text message from the Display information field on MS  101  (e.g., Call forwarded to FwdDN) and resumes the DCCH idle (camping) state. A more detailed description of the feature/function activation/deactivation processing that goes on in the NSP  106  and VAP  103  using the call forward feature/function as an example follows. 
     After the NSP  106  receives the Origination Request [Dialed Digit]  1103  message with the Dialed Digit equal to the Call Forward feature Activation/Deactivation code, the NSP  106  first performs an analysis of the dialed digits to determine if it is a valid feature activation/deactivation code. Next, the NSP checks the user service profile in the WCSD, using the MSID of the originating MS  101 , to determine if the originating MS  101  is authorized for the requested Call Forward feature. The NSP  106  also verifies that the parameters for the feature code are valid. If this validation process is successful, the NSP  106  updates its memory pertaining to feature activation/deactivation for the particular MSID and sends an Origination NACK [Cause, Display]  1104  message to the VAP  103  with the Cause field equal to Call Forward Feature Activation/Deactivation Successful and the Display field information equal to Call forwarded to FwdDN (the forwarding DN dialed with feature code), indicating that feature activation/deactivation is successful. 
     The NSP  106  will take the following actions in response to the MS  101  user entering various codes and different phone numbers to forward a call. As a first alternative, when the feature/function Call Forwarding-Unconditional is entered on MS  101  by the WCS subscriber the NSP  106  checks to see if there is a Call Forwarding feature/function already active for the particular mobile station MS  101 . If a Call Forwarding feature/function is already active then the NSP  106  will update the previous feature/function active code entry and update, for example, the information with a new call forwarding number. Otherwise the NSP  106  will simply create a new feature/function active code entry and the call forwarding number for the mobile station MS  101 . 
     As a second alternative, if the mobile station MS  101  user enters the feature/function code for the Call Forwarding-Programmable Ring feature and the number of rings is specified, the NSP  106  will verify that the number is within a range of acceptable values (i.e., valid). If the number of rings is not a valid number, the NSP  106  will use a default value for the number of rings to use. Next, the NSP  106  will translate the number of rings into an associated number of seconds it will take to execute the desired number of rings and create or modify as necessary the feature entry for the mobile station MS  101  to provide the desired number of seconds for ringing. Thus, this entry will contain the MSID, call forwarding number and the number of seconds ringing is to continue. 
     As a third alternative, if the mobile station MS  101  user enters the feature/function code for the Call Forwarding-Time of Day feature/function, the NSP  106  will verify that the begin time and end time parameters are present and valid. If the time parameters are valid, the NSP  106  will create/modify the feature entry for the mobile station MS  101 . The entry will contain MSID, call forwarding number, begin time and end time. 
     As a fourth alternative, if the mobile station MS  101  user enters the feature/function code for the Call Forwarding-Busy feature/function, the NSP  106  will modify or create the feature entry for the mobile station and store the call forwarding number to be used if an incoming call occurs when the mobile station MS  101  user is, for example, on another call. The entry will contain the MSID, the call forwarding number, and a flag indicating that the call is to be forwarded when the MS  101  line is busy. 
     Furthermore, the MS  101  user may activate a feature, such as call forward, for a particular DN without entering the DN. First, as previously noted, the MS  101  could enter the feature code while on an active call and the feature would be provisioned relative to the DN of the other party involved in the call. Second, feature activation provisioning may be achieved without entering a DN by entering the feature activation code immediately after a call has been disconnected. 
     However, if the mobile station MS  101  user enters the feature/function code for Call Forwarding Feature Deactivation, the NSP  106  will verify that the feature corresponding to the deactivation code is currently active for the mobile station MS  101 . The NSP  106  will then deactivate the feature/function and delete the associated feature information from the subscriber profile. 
     In any case, the NSP  106  will subsequently send out the Origination NACK [Cause, Display]  1104  message to the VAP  103 . The Cause field will containing information such as; Feature Activation Successful, Feature Activation Failed, Invalid MS, Out of Resource, Input Unknown, Feature Deactivation Successful, Feature Deactivation Failed. The Display field will contain information such as Call forwarded to FwdDN. 
     Some examples of possible feature activation and deactivation codes are provided in the tables below for various WCS feature/functions. The activation and deactivation codes for the WCS features/functions, which need to be activated/deactivated when the MS is idle (MS  101  on DCCH), are tabulated below. 
     
       
         
           
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                 Deactivation 
               
               
                 Feature Application 
                 Activation Code 
                 Code 
               
               
                   
               
             
            
               
                 Automatic Callback 
                 *66 
                 *660 or 
               
               
                   
                   
                 MS power 
               
               
                   
                   
                 down/ 
               
               
                   
                   
                 de-registered 
               
               
                 Call Forwarding-Unconditional 
                 *90#DN 
                 *900 
               
               
                 Call Forwarding-Programmable 
                 *91*x#DN, *91#DN 
                 *910 
               
               
                 Ring 
               
               
                 Call Forwarding-Time of Day 
                 *92*hhmm*hhmm#DN 
                 *920 
               
               
                 Call Forwarding-Busy 
                 *93#DN 
                 *930 
               
               
                 Call Return 
                 *69 
                 *690 
               
               
                 Call Screen 
                 *60#DN or *60#n#DN 
                 *600#DN 
               
               
                 Distinctive Ringing 
                 *70#DN or *70#n#DN 
                 *700#DN 
               
               
                 Speed Calling 
                 *75*(1-30)#DN 
               
               
                   
               
            
           
         
       
     
     In the Table 1 above, the DN denotes a directory number (telephone number), the x denotes the number of rings and the hh denotes the hour of day in the format of 00 to 23, mm denotes the minute in the format of 00 to 59. 
     The feature codes of WCS features/functions, which can be initiated when the call is in progress (MS  101  on DTC), are tabulated below in Table 2. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Feature Application 
                 Feature Code 
               
               
                   
                   
               
             
            
               
                   
                 Call Transfer 
                 *77#TransferDN 
               
               
                   
                 Three-way call 
                 *33#ThreeWayDN 
               
               
                   
                   
               
            
           
         
       
     
     One skilled in the art will recognize that the feature/function activation and deactivation codes provided above are purely exemplary and may be different without changing the basic concept of the present invention. 
     Furthermore, as examples of feature/function activation/deactivation, the NSP  106  will take the following actions for various different feature/function codes input by the MS  101 . (1) Call Forwarding-Unconditional: If there is a Call Forwarding feature already active for the particular mobile, the NSP  106  will update the feature entry with the new call forwarding telephone number. Otherwise, the NSP  106  will create a new feature entry for the mobile. (2) Call Forwarding-Programmable Ring: If the number of rings is specified, the NSP  106  will verify that the number is within the range, or it will use the default value. The NSP  106  will translate the number of rings into number of seconds and create/modify the feature entry for the MS  101 . The entry will contain the MSID, call forwarding number and the number of seconds. (3) Call Forwarding-Time of Day: The NSP  106  will verify that the begin time and end time parameters are present and valid. If the time parameters are valid, the NSP  106  will create/modify the feature entry for the MS  101 . The entry will contain MSID, call forwarding number, begin time and end time. (4) Call Forwarding-Busy: The NSP  106  will modify/create the feature entry for the MS  101  and store the call forwarding number. (5) Speed Dialing: NSP  106  will verify the data that is sent by the MS  101  for provisioning. The unique code specified may be, for example, a valid number in the range 1-30, and the DN may be, for example, a number consisting of 1 to 17 digits (a single digit number can be the smallest number that a WCS subscriber can dial to make a successful call, e.g., dial 0 to reach the operator. Seventeen digits may be required to accommodate a call screen for international calls. To make an international call—dial 9 to get out, then 3 number code to make an international call, 2/3 number code for the country, 2/3 number code for the region/area and 7 digit phone number, makes a possible total of 17 digits). The NSP  106  then updates the speed-dialing code list for the MS  101  with the new data provided. In case an entry for the requested unique code already exists, then the current DN will overwrite the existing entry. (6) Call Screen: NSP  106  will verify the data that is sent by the MS  101  for provisioning. The CallScreenDN specified must be a valid number, e.g., it may consist of 4 to 10 digits, and the code signifying the type of treatment may be, for example, from 1 to 3. The NSP  106  then updates the CallScreenDN list for that MS  101  with the new data provided. (7) Distinctive Ringing: If the user sends *70#n#DN, where n is a number from 1 to 5 and DN is a phone number and presses the send button, NSP  106  will verify the data that is sent by the MS  101  for provisioning. The DistinctiveRingingDN specified may be, for example, a valid number consisting of 4 to 15 digits, and the code signifying the type of ring signal may be, for example, between 1 and 5. The NSP  106  then updates the DistinctiveRingingDN list for that MS  101  with the new data provided. (8) Feature Deactivations: The NSP  106  will verify that the feature corresponding to the deactivation code is currently active for the MS  101 . It will then delete the associated feature information from the subscriber profile. 
     In any case, if the validation is unsuccessful because the feature code is invalid or the parameters are missing, a Cause value equal to the Feature Activation/Deactivation Failed and the appropriate Display information regarding the specifics of the failure will be included in the Origination NACK [Cause, Display]  1104  message. 
     When VAP  103  receives the Origination NACK [Cause, Display]  1104  message, the VAP  103  cancels the timer TO 1 , extracts the Display information from the message, and inserts the Display information into the Display field of IS-136 Reorder/Intercept [Display]  1105  message. Next, the VAP  103  send the IS-136 Reorder/Intercept [Display]  1105  message to MS  101  and instructs the MS  101  to return to the idle (camping) state. Similar feature/function activation/deactivation signal flows will be used in the various feature/functions for the WCS as described in more detail below. 
     Although the feature/function activation/deactivation signal flows have been explained using call origination signaling, the signaling and MS  101  user notification may also be achieved using Short Message Services (SMS) signaling with text messages or audio messages over a voice channel. The audio notification can be accomplished by establishing a voice channel between the VAP  103  and the MS  101  and playing a recorded or voice synthesized message, e.g., Call forwarded to FwdDN to the MS  101 . 
     X. Call Hold [KAW-Completed Sep. 19, 1999] 
     Often, a telephone user, particularly a mobile phone user, is preoccupied when an incoming call is received or is interrupted with something of a higher priority during an active call. For example, a mobile telephone user may be in a meeting where the receipt of an incoming call would be a disruption. Thus, there is a need to allow a user to avoid disruption at particular times. However, the mobile telephone user may wish for the call to be temporarily on hold because they will be available in a short period of time. 
     In existing wireless telephone handsets a user can preset her wireless phone so that an action is automatically taken when a call is received. For example, a user can preset a wireless telephone so that an incoming call is forwarded to voice mail. While such systems allow a user to avoid disruption, they do not allow a user that may be available in the immediate future, e.g., in a few seconds, to subsequently connect with the call that has been directed to voicemail, i.e., to delay receipt of the call until the user is available. In the alternative, existing wireless telephone systems allow a user to place a call on hold during an active call, for example, after answering an incoming call. However, answering the call immediately only to place the call on hold is also disruptive. 
     The call hold feature of the present invention enables existing wireless handsets to provide a user with the ability to interactively place an incoming call on hold in real time without first answering the call. A user, who does not wish to be interrupted or needs to carry on a private conversation off-line can either postpone answering an incoming call without first becoming involved in an active phone call conversation or by placing a presently active call on hold. According to one such embodiment, the calling party can be coupled to, for example, a voice processing unit (VPU) to receive a message that indicates the call is on hold and the called party (WCS subscriber) will be with them shortly. The WCS call hold feature allows the MS  101  user to reroute an incoming call to the VPU without answering the incoming call even though the incoming call is in the process of being automatically routed to the voice mail system (VMS). Thus, the WCS of the present invention provides a-user with the ability to instantaneously place an incoming call on hold in real time or interrupt an incoming call routed to a VMS without first answering the call, have the caller automatically instructed that the call is on hold, and to pickup the call sometime in the near future. Therefore, the present invention allows a mobile phone subscriber to place an incoming call on hold without first having to answer the call as well as allowing a mobile phone user to place an active call on hold. A detail discussion of the WCS call hold feature/function follows. 
     FIG. 12 shows an illustrative communications system in which the call hold feature of the present invention can be implemented. A public switched telephone network (PSTN)  125  is connected to a plurality of communication networks, including one having a telephone  1215 . The PSTN  125  can be coupled to a plurality of local digital switches, such as (LDS)  104 . As previously noted, the LDS  104  may be a TR-08 and/or GR-303 compatible switch which employs distributed intelligence, process-oriented software, and coordinated autonomous computing elements to provide a flexible, modular, reliable and robust digital switching system. Exemplary, but not limiting, LDSs include the 5ESS manufactured byLucent Technologiesand the DMS-100/500 manufactured by Nortel. The LDS  104  can provide a single platform for advanced services including ISDN, Centrex, Custom Calling, and Advanced Intelligent Network (AIN) capabilities. The LDS  104  provides the switching fabric, administration, message switching and call switching functions. 
     The LDS  104  may be coupled to network server platform (NSP)  106  by an X.25 link  4  (packet switched data network link) and an SS7 link  5  (signaling system for call setup and database transactions). The X.25 link  4  carries call control messages on the D-channel between the NSP  106  and LDS  104  that are destined for VAPs  103 A and  103 B. The SS7 link  5  between the NSP  106  and LDS  104  carries the AIN (Advanced Intelligent Network) messages that directs the LDS  104  for proper routing of a call to a user who is a WCS subscriber. 
     NSP  106  may include, among other elements, a controller  1230 , a voice processing unit (VPU)  1235 , memory  1240 , and communications bus (CB)  1238 . The NSP  106  provides voice access ports (VAPs)  103 A,  103 B of the wireless centrex system with control and related operations, administration, maintenance, and provisioning (OAM&amp;P) functions. Control functions include, but are not restricted to, mobile station and mobility management, call control, and feature applications. The NSP  106  is responsible for, among other functions, network intelligence for the VAP  103 , validation, registration, and mobility management. 
     The LDS  104  may, for example, be connected to a RDT  102  by a Bellcore standard GR-303 interface  1 . The GR-303 standard defines digital transmission facility interfaces such as DS 1  and SONET, concentration options between the LDS  104 /IDT  105  and the RDT  102 , signaling options, and call processing and operations data links. The GR-303 interface  1  can be transported across metallic (e.g., T1, ISDN: PR2 or DS3) or fiber-optic (e.g., SONET OC3 or OC12) links. The GR-303 interface  1  carries the voice traffic and the signal traffic for the LDS  104  and the NSP  106 . 
     The PSTN  125  may also be coupled to a mobile switching center (MSC)  1250 . The MSC  1250  generally has functionality similar to the combination of LDS  104  and NSP  106 , and operates to control a cellular telephone network. Mobile switching center architectures are known in the art, and it will be appreciated that any known MSC may be adapted for use with the present invention. Plural base stations are controlled by the MSC  1250 , such as base station (BS)  1255 . Mobile Stations (MS) can travel throughout the cellular network and within the WCS network. Depending on a number of factors, calls involving a mobile station are handled by a base station that provides coverage for the area in which the mobile station is located. Handoff of calls involving the mobile station from one base station to another is controlled by the MSC  1255  in a known manner. A mobile station (MS)  101  is wirelessly coupled to BS  1250  as shown. 
     On the other hand, when MS  101  enters the picocell area of a VAP in the WCS system, handsoff does not occur unless MS  101  has previous authorization to operate within the WCS system. In fact, if the WCS is constructed with security features/functions for restrictive access, the VAP  103  will deny registration and disconnect MS  101  from all macro and micro cell base stations. 
     A more detailed representation of the elements of an illustrative WCS are depicted in FIGS. 1A-1C, and include, among other elements, the VAPn  103 A and  103 B and two mobile communications units, e.g., IS-136 digital TDMA cellular/PCS phones, MS  101 A and  101 B. Also shown are plain old telephone service (POTS)  108  and integrated services digital network (ISDN)  109 . 
     Illustrative implementations of the functions for the call hold/unhold feature of the present invention will now be described in connection with a wireless centrex system. However, it should be understood that the call hold/unhold feature service could also be supported in existing macro cellular systems including an MSC and BS, if properly designed. In such a system, the MSC  1250  and BS  1255  would be programmed to be the functional equivalent of the WCS system including NSP  106  LDS  104 , RDT  102  and VAP  103  combined. However, it is noteworthy that the macro cellular system can not support ISDN and POTS wireline telephones but the WCS system can because it is integrated into such existing systems. 
     FIG. 13 shows the call flow for setting up an incoming call (i.e., call termination) similar to the call flow for setting up an incoming call illustrated in FIG.  5 . For purposes of this discussion, it will be assumed that a calling party (e.g., telephone  1215 ) coupled to the PSTN  125  (or connected to the same LDS) dials the phone number (DN) of the mobile unit  101  and MS  101  is geographically within the WCS transmission picocell area. 
     The call with the DN arrives at the LDS  104  from the PSTN  125 . The LDS  104  receives the ISUP (integrated services digital network user part) IAM (initial address message)  508  message from the PSTN  125  (or a Q.931 setup message). The LDS  104  determines whether the DN is provisioned for AIN termination attempt trigger (TAT), i.e., whether the DN is associated with a WCS authorized MS. If so, the LDS  104  suspends delivery of the call and sends an AIN query message TCAP (AIN Termination_Attempt [DN])  509  to the NSP  106 . The NSP  106  determines whether the subscriber&#39;s mobile unit MS  101  is active and idle in its serving area. If so, the NSP  106  pages the mobile unit MS  101  by sending a Page Request [FDN, MSID]  510  message through the VAP  103  using IS-136 established paging procedures, and starts the TT 6 -paging response timer. As part of the Page Request  510  message, the NSP  106  sends the VAP&#39;s ISDN forward directory number (FDN) and mobile station identification number (MSID) that the VAP  103  uses to complete the incoming call setup procedure. 
     The mobile unit MS  101  responds to the page by sending an IS-136 Page Response  529  message to the VAP  103 . The VAP  103  forwards the Page Response message using Page Response  511 , to the NSP  106  and starts event timer TT 5  to prevent permanent holding of RF and ISDN B-channel resources. When the NSP  106  receives the Page Response  511  message, it cancels the TT 6  timer and knows that MS  101  is available to receive the incoming call and that the VAP  103  has the resources to support the incoming call. At the direction of the NSP  106 , the LDS  104  forwards the call to the FDN of the VAP  103  (e.g., in a TCAP conversation package) serving the mobile unit MS  101 . The NSP  106  also indicates its interest in the event (O_No_Answer for FDN) by sending next event list (NEL) information to LDS  104  in a request component that accompanies the routing component in a conversation package (i.e., TCAP (AIN Forward Call [FDN], NEL [O No Answer])  512  message). 
     The LDS  104  starts a no answer timer (T(NoAnswer ) 531 )) for the FDN and sends an ISDN Q.931 Setup [FDN]  513  message to the VAP  103 . Upon receipt of the ISDN Q.931 Setup [FDN]  513  message, the VAP  103  cancels the TT 5  timer, invokes B-channel call processing, initiates an IS-136 digital traffic channel (DTC) designation to the mobile unit MS  101 , starts the TT 2  timer, and sends a ISDN Q.931 Call Proceeding  514  message to the LDS  104 . 
     The mobile unit MS  101  tunes to the designated DTC and sends an indication message, MS on DTC  515 , to the VAP  103 . When the VAP  103  detects that the mobile unit MS  101  is on the requested traffic channel through a Digital Verification Color Code (DVCC; a layer  2  signal from the MS) status change, it cuts through the ISDN/B-channel and initiates the alerting procedures for each call leg, that is upstream to the LDS  104  and downstream to the mobile unit MS  101 . In particular, the VAP  103  sends an IS-136 Alert-with-info  516  message to the mobile unit MS  101 , starts the Alert timer (TT 3 ), and sends an ISDN Q.931 Alerting  518  message to the LDS  104 . When the mobile unit MS  101  receives the Alert-with-info  516  message, it notifies the user through, for example, ringing (or an audible noise, vibrating, indicator lights, or a visual message display) that there is an incoming call (i.e., someone is calling them). When the LDS  104  receives the ISDN Q.931 Alerting  518  message, it sends an ISUP ACM (address complete message)  519  message to indicate that the Mobile Station MS  101  is available and communicating with the VAP and switches in the PSTN  125 , and generates a ringback tone  520  that is heard by the calling party. 
     The mobile unit MS  101  returns an alerting acknowledge, IS-136 Mobil ACK  517 , message to the VAP  103  so that the VAP  103  knows that MS  101  is alerting the user that there is an incoming call. Responsive to the alerting acknowledge message, the VAP  103  cancels the TT 3  timer, starts a TT 4  timer, and enters the wait-for-answer call processing state. If the MS  101  user answers (accepts) the call by, for example, pushing a send (or talk) key on the mobile station, the mobile station MS  101  sends an IS-136 Connect  521  message on the FACCH to the VAP  103 . In response, the VAP  103  cancels the TT 4  timer and sends an ISDN Q.931 Connect  522  message to LDS  104 . After receiving the Connect message, the LDS  104  cancels the T(NoAnswer)  531  timer, and sends ISUP ANM (answer message)  523  message to the switch in the PSTN  125  and cuts through the voice path. Next, the LDS  104  sends an ISDN Q.931 Connect ACK  524  acknowledge message to the VAP  103  and then sends a TCAP Completed  525  message to the NSP  106  (using TCAP response) to complete the TCAP transaction. After receiving the ISDN Q.931 connect ACK  524  acknowledge message, the VAP  103  sends a Termination Result [Success]  526  message (i.e., call connected) to the NSP  106  to indicate that the incoming call has been successfully connected to the mobile station MS  101  and to trigger billing (air interface usage) and other OAM&amp;P activities. A voice path  527  is then established between the calling party and the mobile unit MS  101 . Once the call has been connected and a voice path established the mobile station MS  101  user can place the active call on hold as described below. 
     If the MS  101  user does not answer the incoming call the T(NoAnswer) timer will expire and the incoming call will be handled according to the mobile station MS  101  user&#39;s preprogrammed default designation. For example, the call could be forwarded to the VMS  107 , the call could be forwarded to the MS  101  associated desk top phone  108 , or the incoming call may be allowed to continue alerting the mobile station (MS) indefinitely until the caller hangs up the telephone. 
     FIG. 14A shows the call flow for a first preferred embodiment illustrating implementation of the call hold/unhold feature performed on an active call. For purposes of this discussion, it will be assumed that there exists an active call between a mobile station MS  101  in a WCS and a calling party (e.g., using POTS telephone  1215 ) coupled to the PSTN  125  and the call has been established either by a caller using POTS  1215  initiating a call to MS  101  (i.e., as just described with reference to FIG.  13 ), or vice versa. In any case, an Active Call  1401  is in progress and the mobile station MA  101  user decides to place the active call on hold. 
     When the mobile user generates a hold command by, for example, pressing a hold button on their MS  101 , an IS-136 call-hold request message  1402  is sent over the FACCH (fast associated control channel) from the MS  101  to the VAP  103  (with which the MS  101  is registered). The VAP  103  interprets the request message, stops processing voice traffic frames, and notifies the NSP  106  that there is a call on hold  1404 . Also, in response to the request message, the VAP  103  sends an IS-136 Call-Hold Request Ack  1403  acknowledge message to the MS  101 . The VAP  103  continues to monitor the FACCH and also informs the NSP  106  that the call is on hold (Call on hold  1404 ). In response the NSP  106  will send a Call on hold Ack  1405  message. If a personalized message has been pre-recorded by the MS  101  user, the Call on hold Ack  1405  message will contain the personalized message, i.e., the Call on hold Ack (personalized message)  1405  message will be provided from the NSP  106  to the VAP  103 . 
     When the VAP  103  places the call on hold, it may direct, for example, its own DSP (digital signal processor) to send a message and/or white noise (comfort noise such as music)  1406  to the calling party and/or the MS  101 . The message and or white noise can be used to let the parties know that the call is still active and on hold. During the period that white noise is sent to the MS  101 , the MS  101  can continue to transmit traffic frames, but the VAP  103  will ignore the frames. Further, the VAP  103  may also ignore voice traffic transmitted from the calling party. 
     When the MS  101  user generates an unhold command by, for example, pressing the hold button again, the MS  101  transmits an IS-136 Call-Unhold Request  1407  message on the FACCH to VAP  103 . Upon receipt of the request message, the VAP  103  performs several actions. The VAP  103  informs the NSP  106  that an active call has been resumed  1409  and also instructs its DSP to stop generating white noise, if provided. The VAP  103  again begins to process traffic frames (e.g., voice traffic) received from the MS  101  and sends the frames to the calling party and again process voice traffic  1408  from the calling party directed to the MS  101 . The VAP  103  also transmits a IS-136 Call-Unhold Request Ack  1408  acknowledge message to the MS  101  to indicate that the call is resumed. 
     FIG. 14B shows the call flow for a second preferred embodiment illustrating implementation of the call hold/unhold feature performed on an active call. For simplicity, this signaling flow only discusses how the system reacts to the feature when there is only one call for the MS  101 . For interactions with other features, e.g. Three-way Call, refer to that section for more information. 
     First, the call is in progress, Call in progress  1420 , and the MS user presses, for example, the send button on MS  101 . An IS-136 Flash With Info  1421  message is sent to the VAP  103 . The VAP  103  sends an IS-136 Flash With Info ACK  1423  message to the MS  101  and sends a Feature Request [FlashWithInfo]  1422  message to the NSP  106  which indicates that the MS  101  user is initiating a call hold. When the NSP  106  receives the Feature Request [FlashWithInfo]  1422  message from the VAP  103 , it analyses the message and confirms that the mobile is not involved in a 3-way call. If the current call reference indicates that this is a three-way call, the Flash-With-Info message received by the NSP will be examined with different set of rules similar to those described in the section herein related to conference calling. The NSP  106  then interprets the message as a request for Call Hold and validates that the MS  101  is authorized to the Call Hold feature. If the validation is successful, the NSP  106  sends a Feature request ACK [Call Hold]  1424  message to the VAP  103 , the action field being designated as Call Hold. If the MS  101  is not authorized to use Call Hold feature, the NSP  106  ignores the Feature Request [FlashWithInfo]  1422  message. Further, the NSP  106  may, but not need, send a Feature Request NACK message to the VAP  103  because the VAP  103  has no action to take upon such a message. It may play a voice prompt or send a short message to the user in such a case for future releases of the feature. 
     Next, the VAP  103  sends Q.932 Hold  1425  message to the LDS  104  and starts a THh timer. In response, the LDS  104  sends a Q.932 Hold ACK  1426  message to the VAP  103  and the VAP  103  stops the THh timer. The call is placed on hold with the LDS  104 , Call held  1427 . However, if the VAP  103  receives a Q.932 Hold NACK message from the LDS  104  it will send out a Call Held [Fail] message to the NSP  106 . Further, if the timer THh expires, the VAP  103  will log an error and send out a Call Held [Fail] message to the NSP  106 . 
     Next, the VAP  103  sends a Call Held [success]  1428  message to the NSP  106 , and if provisioned, plays a voice prompt to inform the user that the call is on hold and/or music (VAP plays voice and/or music  1429 ), and starts TH 1  timer. However, if the NSP  106  gets a Call Held [fail] message form the VAP  103 , it will modify the call information record (if needed) and the call will remain in a ‘talk’ state. 
     When the MS  101  user wants to retrieve the call it presses, for example, the send key or the hold key again on the MS  101  and IS-136 Flash with Info  1430  message is sent to the VAP  103 . When the VAP  103  receives the IS-136 Flash with Info  1430  message, the VAP will look at the appropriate record to find that this message has come for a call which is currently on hold. The VAP  103  stops the TH 1  timer and sends back an IS-136 Flash With Info Ack  1431  message to the MS  101 . Since the VAP  103  has determined that this is a request to retrieve the held call, it sends a Q.932 Retrieve  1432  message to the LDS  104  and starts the TRr timer. However, if the TH 1  timer expires, the VAP  103  shall play a voice prompt (optional) to the user informing him that the call is being disconnected. It shall then follow, for example, the VAP  103  OA&amp;M Release procedure and release the call. 
     When the VAP  103  receives a Q.932 Retrieve ACK  1433  message from the LDS  104 , it cancels the TRr timer and sends a proprietary Call Retrieve [success]  1434  message to the NSP  106 . However, if the VAP  103  receives a Q.932 Retrieve NACK message from the LDS  104 , it will send out a Call Retrieved [Fail] message to the NSP  106 . Further, if the timer TRr expires, the VAP  103  will log an error, send out a Call Retrieved [Fail] message to the NSP  106  and initiate, for example, a VAP  103  OA&amp;M Release procedure. 
     Then, the NSP  106  modifies the call record information to indicate that a call is in progress with MS  101 . If the NSP  106  receives a Call Retrieved [fail] message from the VAP  103 , it shall stop the TH 2  timer and update its call information record. Further, if the timer TH 2  expires, the NSP  106  will initiate, for example, an OA&amp;M Release procedure. Finally, the call is retrieved and resumes as Call in progress  1435 . 
     As indicated above, another embodiment of the call hold feature/function may include the use of a personalized message to be used prior to, or in place of, a system default voice prompt and comfort noise (e.g., music) when a call is placed on hold. The MS  101  user may use the VPU  1235  to record personalized messages for the call hold feature/function. If the MS  101  user enters a special feature access code, for example *70, to initiate recording a personalized message recording in the VPU  1235 . The NSP  106  validates the MS  101  and assigns call resources to the MS  101 . Then the VPU  1235  prompts the user to record their personalized greeting. Once the greeting is completed, the NSP  106  stores it in, for example memory  1240 , for the MS  101  user in their subscriber profile. Next, the NSP  106  frees the call resources. If the user wishes to modify or delete their personalized greeting they may enter another feature code, for example *71. 
     When the user is on an active call and invokes the call hold feature/function, a message is sent by the VAP  103  to the NSP  106  indicating invocation of the feature. In response, the NSP  106  checks against the subscriber DB stored in, for example memory  1240 , to determine if there is a personalized greeting available for the MS  101  user that may be used for a call hold. If there is a personalized greeting for the MS  101  user, the NSP  106  sends it to the VAP  103  and may be included as part of a call hold acknowledgement message. When the VAP  103  receives the call hold acknowledgement message, if there is a personalized greeting for MS  101 , it will play that to the calling party of PSTN  125 / 1215 . If there is no personalized greeting for the MS  101  user, the NSP  106  may send a call hold acknowledgement message without any personalized message and the VAP  103  will play some other default message, for example, a system default generic message indicating that the call has been placed on hold. In either case, the VAP  103  may subsequently play comfort noise, e.g. music to the calling party placed on hold. Alternatively, the VAP  103  may play the comfort noise to both parties without any prior message. Although this personalized greeting feature is described with respect to call hold, it may also be used in conjunction with call screen and distinctive ringing feature/functions as well. 
     FIG. 15 shows the call flow for an illustrative implementation of the call hold/unhold feature for an unanswered incoming call. As with FIG. 13, it will be assumed that a calling party (e.g., telephone  1215 ) coupled to the PSTN  125  (or at the same LDS) dials the phone number (DN) of the mobile unit MS  101  and MS  101  is within the transmission service picocell area of the WCS. 
     When the mobile unit MS  101  receives an incoming call, the mobile unit MS  101  can alert the user of the incoming call by, for example, ringing or other audible noise or alerting methods. Also, caller ID information can be provided that shows up on a display of the mobile unit MS  101 . FIGS. 5 and 13, as discussed above, shows the call flow for delivery of and answering of an incoming call. However, rather than answer the incoming call the mobile station MS  101  user can decide to place the incoming call on hold before answering it (i.e., before pressing, for example, a send key (e.g., talk, on, yes, answer, etc.) on MS  101  and initiating a personal conversation with the caller). Rather than answer the call immediately, the mobile station MS  101  user can accept the call without answering it by first putting the incoming call on hold as described below. 
     Upon being alerted of the incoming call, a user  1520 , not wishing to answer the call immediately, can generate a hold command by, for example, pressing a hold button on the mobile unit MS  101  or entering a feature code (e.g., *95). When the user inputs a hold command, the call is accepted (i.e., connected) and put on hold rather than being answered and a voice path being cut to the mobile station MS  101 . However, when the call is accepted, resources including a traffic (e.g., voice) channel are allocated for the call and white noise or an announcement will be provided. Also, the call is connected in the same manner as described above and shown in FIGS. 5 and 14 illustrated as step  1506 . 
     The VAP  103  receives a call hold request via an IS-136 Call-Hold Request  1505  message from the mobile unit MS  101  and sends, for example a personalized message or a default message, e.g., a generic system call on hold announcement to the calling party (Call on hold announcement to originating party on DTC  1508 ). The VAP  103  also sends an IS-136 Call Hold Request ACK  1507  acknowledge message to the mobile unit MS  101  and notifies the NSP  106  that the mobile unit MS  101  has put the call on hold (call on hold  1510 ). Thus, the call is placed on hold with the VAP  103  and the VAP notifies the NSP  106  using the Call on hold  1509  message. 
     A DSP in, for example, the VAP  103  may send a message or comfort noise (i.e., white noise such as music) to the user of the mobile unit MS  101  and to the calling party while the incoming call is on hold. In the alternative, the VPU  1235  may play a short message (announcement) sent to the VAP  103  via a call on hold Ack message indicating the call is on hold prior to the DSP sending a system default message or comfort noise. While the call is on hold, the mobile unit MS  101  can continue to transmit traffic frames, but the VAP  103  will ignore the frames. Further, the VAP  103  may ignore voice traffic transmitted from the calling party (e.g., mute). 
     When the user of the mobile unit MS  101  desires to retrieve the held call, the user can generate an unhold command by, for example, pressing the hold button (or feature code) again  1511  on the mobile unit MS  101 . In response, to a call unhold command, the mobile unit MS  101  sends an IS-136 Call-Unhold Request  1512  message on the FACCH to the VAP  103 . The VAP  103  interprets this message and directs the DSP to stop sending white noise, if provided. In response to message, the VAP  103  begins to process traffic frames received from the mobile unit MS  101  and sends the same to the calling party. The VAP  103  sends a notification to the NSP  106  that the call is no longer on hold and has become active (call resumed  1514 ). Also, the VAP  103  begins processing the voice traffic from the calling party transmitted to the mobile unit MS  101 , thus establishing an Active Voice Call  1515 . 
     According to another illustrative embodiment of the present invention, the call hold button can act similar to a call mute button when a call is placed on hold, by for example pressing the hold button twice quickly. In this implementation, the mobile unit MS  101  can receive voice traffic from the calling party, while the calling party is muted from any voice traffic generated by the called party. In this instance, the calling party may receive white comfort noise when on hold. This call muting type functionality creates one way voice traffic transmission. Such an implementation may be beneficial in allowing the calling party to communicate a brief message to the called party at any time after the call has been placed on hold. Thus, if a calling party has an emergency message or an important message that cannot wait, the called party may receive this message in real time. 
     In one embodiment a call hold announcement may be played to the called party or an alert is provided to the called party to remind them that the a call is on hold. During the announcement to the called party the one-way communication line can be temporarily shut off or optionally open for voice traffic. As previously noted, a call hold announcement may also be sent to the calling party. The call hold announcement may be repeated to the calling party and/or the called party at predefined intervals (e.g., every 30 seconds) subsequent to initiation of the call hold. 
     Furthermore, in another embodiment, the call hold feature may allow a calling party to interactively transfer to a voice mail system or send an alphanumeric message to the called party rather than simply wait on hold. For example, when a call is on hold the VPU  1235  can notify the calling party the they may leave a message in the called party voice mail by entering a particular set of key strokes (e.g., *34#) or enter any alphanumeric message using their telephone key pad. The NSP  106  will respond to the input by the calling party and instruct the LDS  104  to route the input accordingly to either the VMS  107  or the MS  101 . A more detailed discussion of the announcement features and additional features related to user proactive call handling follows. 
     XI. User Proactive Call Handling 
     Another feature of the present invention provides user proactive call handling (UPCH) functionality. This feature allows a mobile telephone user to proactively handle a call in an intelligent wireless communications system. One aspect of this feature allows a user to process and terminate an incoming call in real time. Another aspect of the UPCH feature provides the ability to delay allocation of the voice channel to a called party until when, if at all, the incoming call to the called requires a voice channel. 
     According to an illustrative embodiment of the present invention, a subscriber is notified of an incoming call via a Short Message Service (SMS) message with caller ID or a user alert, such as a tone or ringing. Upon receipt of the alert, the subscriber may select from a series of options, how to process and terminate the incoming call. For example, if an incoming call is of high priority and requires immediate attention, the subscriber may decide to answer the call immediately. If the subscriber decides that the call does not require immediate attention, he may opt to provide a delayed answer. Such a delayed answer option can involve connecting the call to an announcement prior to answering the call. Still further, if neither of the prior options is suitable, then the subscriber may opt to send the call to a voice mail system, from which a recorded message can later be retrieved. Yet another option of terminating the call is to forward the call to another phone. In the event that the subscriber decides that the incoming call should not be answered, the subscriber may choose to reject the call. If the subscriber decides that none of the aforementioned options should be proactively taken, then a default option can be used to terminate the call. Such a default option may include, but is not limited to, forwarding the call, delaying the answer, sending the call to a voice mailbox, or rejecting the call. A detailed discussion of the systems and methods for implementing UPCH features/functions in a WCS follows. 
     The UPCH feature, like the call hold feature of the present invention, can be implemented using the illustrative communications system of FIG. 12. A public switched telephone network (PSTN)  125  is connected to plural communication networks, including one having a telephone  1215 . The PSTN  125  can be coupled to a plurality of local digital switches, such as local digital switch (LDS)  104 . The LDS  104  may be coupled to network server platform (NSP)  106  by an X.25 link  4  and an SS7 link  5 . NSP  106  may include, among other elements, a controller  1230 , a voice processing unit (VPU)  1235 , memory  1240 , and communications bus (CB)  1238 . The NSP  106  provides voice access ports (VAPs)  103 A,  103 B of a wireless centrex system with control and related operations, administration, maintenance, and provisioning (OAM&amp;P) functions. Control functions include, but are not restricted to, mobile station and mobility management, call control, and feature applications. The NSP  106  is responsible for, among other functions, network intelligence, validation, registration, mobility management, and serves as a message center. 
     The X.25 link  4  carries call control messages on the data channel (D-channel) between the NSP  106  and LDS  104  that are destined for the VAPs  103 A and  103 B. The SS7 link  5  between the NSP  106  and LDS  104  carries the AIN (Advanced Intelligent Network) messages that direct the LDS  104  for proper routing of call to a user who subscribes to wireless centrex system (WCS) services. 
     The LDS  104  may be connected to a remote digital terminal (RDT)  102  by a Bellcore standard GR-303 interface  1 . The GR-303 standard defines digital transmission facility interface such as DS1 and/or SONET, concentration options between the integrated digital terminal (switch)  105  and the RDT  102  signaling options, and call processing and operations data links. Thus, the GR-303 interface  1  can be transported across metallic (e.g., T1, ISDN:PR1 or DS3) or fiber-optic (e.g., SONET OC3 or OC12) links. The GR-303 interface carries the voice traffic and the signal traffic for the LDS  104  and the NSP  106 . 
     The PSTN  125  is also coupled to a mobile switching center (MSC)  1250 . The MSC  1250  has functionality similar to the combination of LDS  104  and NSP  106 , and operates to control a cellular telephone network. MSC architectures are known in the art, and it will be appreciated that any MSC may be adapted for use with the present invention. Plural base stations (BS), for example like the one BS  1255 , are controlled by the MSC  1250 . Mobile stations MS  101  can travel throughout the cellular network and into the WCS network. Depending on a number of factors, calls involving a mobile station are handled by a base station BS  1255  that provides cellular coverage for the area in which the mobile station is located. Handoff of calls involving the mobile station MS  101  from one base station BS  1255  to another base station BS  1255  is controlled by the MSC  1250  in a known manner. A mobile station MS  101  may be wirelessly coupled to BS  1255  as shown or alternatively to a VAP  103  for communication connection to other telephones within the entire PSTN, cellular telephone, and WCS configuration. Thus, the WCS can connect to a macro cellular SS7 network to support integrated mobility functions including terminal handoff and personal roaming features. 
     On the other hand, as illustrated in FIG. 1, a WCS can operate as a wireless system without being connected to a public macro cellular system, and thus not support mobility functions associated with the macro cellular system. 
     An illustrative implementation of the UPCH service of the present invention will be described in connection with a wireless centrex system. However, it should be understood to those skilled in the art that the UPCH service can also be supported in existing macro cellular systems. In such a system, the MSC  1250  can provide similar functionality to the NSP  106  plus the LDS  104 , and a BS  1255  is functionally similar to a VAP  103 . 
     FIG. 16 provides an exemplary call flow diagram for activating the UPCH feature according to an illustrative embodiment of the present invention. To activate the UPCH service, a subscriber enters an Feature Activation Code (FAC)  1601  (e.g., *1) on his mobile station MS  101  and presses, for example, a SEND button or some other designated key stroke. An IS-136: Call Origination&lt;FAC&gt;  1602  message is sent to, for example, VAP  103 A which forwards the message upstream through the RDT  102  and LDS  104  (not shown) to the controller  1230  of the NSP  106  as Call Origination &lt;FAC&gt;  1603  message. The controller  1230  updates information for the subscriber in memory  1240  that includes a database, and sets the UPCH service feature active for the subscriber at step  1604 . 
     The controller  1230  of the NSP  106  then sends UPCH FAC ACK  1605  acknowledgment message back to the subscriber&#39;s mobile station MS  101 A through the LDS  104 , RDT  102  (not shown) and VAP  103 A (UPCH FAC  1606 ). After the acknowledgement signal has been received a character on the mobile station MS  101 A, for example on a display screen, may be illuminated to indicate that the UPCH service is active. 
     The database in memory  1240  may contain, among other things, a profile for each subscriber including services available to the subscriber and preferences of the subscribers which can be dynamically changed by a subscriber telephonically, over the Internet, or otherwise. 
     If a subscriber desires to deactivate the UPCH feature, the subscriber can enter a feature deactivation code FDC (e.g., the AFC code plus *3) and press, for example, the SEND button on his mobile station MS  101  as shown in step  1607 . An IS-136 Call Origination &lt;FAC*3&gt;  1608  message having the feature deactivation code is then sent upstream to the controller  1230  of the NSP  106  by way of, for example, the VAP  103 , RDT  102 , (not shown) and LDS  104  (Call Origination &lt;FAC&gt;  1609 ). The controller  1230  of the NSP  106  updates the subscriber&#39;s profile in memory  1240  by setting a UPCH feature flag inactive. The controller  1230  of the NSP  106  may then send an acknowledgment message, UPCH FDC ACK  1611 , back to the subscriber&#39;s mobile station MS  101 A through, for example, the LDS  104 , RDT  102  (not shown) and VAP  103 A (UPCH FDC ACK  1612 ). After the acknowledgement signal has been received by the MS  101 , an UPCH indicator on the mobile station MS  101 A may be turned off to indicate that the UPCH service is inactive. 
     Another illustrative implementation of the UPCH service feature will now be described in connection with call flow diagram of FIG.  17 . An incoming call  1701  to a mobile station MS  101 A is delivered to the controller  1230  of the NSP  106 . The incoming call  1701  can originate anywhere in the communications network including from a caller in a cellular system (e.g., MS  101 ), wireless centrex system (e.g., mobile station MS  101 B), the PSTN  125  (e.g., landline phone  1215 ), or any local and long distance network. 
     The controller  1230  retrieves profile information  1702  associated with the called party from the memory  1240 . If the UPCH active flag is set for the called party, the controller  1230  can send a short message (SM) &lt;Reason, Caller ID&gt;  1703  to the VAP  103 A with which the called party mobile station MS  101 A has registered. The SM transmitted to the called party indicates that an incoming call exists and may further include caller ID data such as the calling party&#39;s name and/or number. 
     The short message may be transmitted to the called party in a portion of the DCCH known as a short message service channel (SMSCH). An exemplary implementation of the short message is described in the IS-136 EIA/TIA Interim Standard. The SMSCH can carry signal information for set up and delivery of short alphanumeric messages from the NSP  106  to the mobile station  101 A of the called party. The SMSCH is a logical sub-channel of the SMS point-to-point messaging, paging, and access response channel (SPACH), which is a logical channel of the DCCH. The DCCH operates on a set of frequencies separate from those used to support cellular conversations, which may be carried on the DTC. 
     After the SM  1703  is received by the VAP  103 A at which the called party&#39;s mobile station MS  101 A is registered, according to this illustrative embodiment, the VAP  103 A follows the IS-136 specification by first sending a SPACH Notification  1704  message to the called party&#39;s mobile station MS  101 A. The mobile station MS  101 A sends a SPACH Confirmation  1705  acknowledgement message to VAP  103 A and then the VAP  103 A sends RDATA  1706  message including the short message SM to the mobile station. Thereafter, the mobile station MS  101 A acknowledges receipt of RDATA by sending RDATA Accept  1707  message back to the VAP  103 A. 
     When the short message is delivered to the called party, it is displayed on the called party&#39;s mobile station MS  101 A. Thus, the called party knows that an incoming call exists and the identity of the caller through the caller ID information displayed on the called party&#39;s mobile station. The called party then can decide how to handle the incoming call. Options available to the subscriber may include: a) answer the call immediately; b) delay answering the call; c) immediately forward the call to voice mail; d) forward the call to another number; e) reject the call; f) send a short message to the calling party; and g) take no action. The calling party can select an option by, for example, pressing one or more keys on the mobile station keypad of pressing a touch screen. A discussion of the operation of some of the possible mobile station MS  101  user UPCH selections follows. 
     According to a first aspect of the UPCH feature implementation, when the called party desires to answer the incoming call immediately he depresses a button or key (e.g., TALK or SEND) at the mobile station MS  101 A. A call origination message is then transmitted upstream in the DCCH to the VAP  103 A and up to the LDS  104  and NSP  106 . The NSP  106  immediately allocates a voice channel between the LDS  104  and the mobile station  101 A that connects with the voice path previously established between the calling party and LDS  104  when the calling party first initiated the call, to thus establish a point-to-point voice channel between the calling and called party. High priority may be given to the called party&#39;s request for a voice path e.g., a DTC channel may be quickly allocated. 
     According to a second aspect of the UPCH feature, a MS  101  user may chose to delay answer of a call and would enter a different function code, for example, pressing “*1, Send”. This key stroke would forward the incoming call to an announcement stored in the voice processing unit (VPU)  1235  of the NSP  106 . FIG. 18 shows an exemplary call flow diagram for the delay answer call option in accordance with an illustrative embodiment of this aspect of the present invention. 
     First, an incoming call is provided with a voice path  1801  between the calling party and LDS  106 . The LDS  106  passes the incoming call  1701  including a route query to the controller  1230  of the NSP  106 . The controller  1230  retrieves the profile of the called party from memory  1240 . If the UPCH service is active for the called party, a short message SM &lt;Reason, Caller ID&gt;  1703  is sent to the mobile station MS  101 . As described above and shown in FIG. 17, steps  1704 - 1707  follows and the user is provided an opportunity to determine in real time how to handle the incoming call. 
     The called party receives the message and decides that he wants to answer this call after some delay. So the called party enters a delay answer feature code such as “*1 SEND”  1808  and an IS-136: Call Origination  1809  message, with “*1” as the keyed input, is sent upstream to the NSP  106  by way of VAP  103 A (Call Origination  1810 ). The controller  1230  receives the message, updates the called party&#39;s database in memory  1240  with current status information, and instructs the LDS  104  using Reroute to VPU  1811  to connect the calling party&#39;s voice path to the VPU  1235 . The VPU  1235  plays a brief message, such as “Please wait, [the called party name] will be with you shortly” in step  1812  and places the call on hold (with or without white noise generated by a DSP). 
     When the called party subsequently becomes available and desires to be connected with the on hold calling party, he enters a key feature code such as “*7 SEND” in step  1813 . An IS-136: Call Origination &lt;FC*7&gt;  1814  message, with “*7” as the feature code, is sent to VAP  103 A which forwards the Call Origination  1815  message to NSP  106 . The controller  1230  of the NSP  106  receives the message, updates the status of the called party in memory  1240 , and retrieves the active call information. If the calling party is still holding, the controller  1230  instructs the VAP  103 A to barge into the voice path established between the calling party and VPU  1235  (or DSP), establishing a three-way connection. Then, the controller  1230  instructs the VPU  1235  (or DSP) to disconnect from the voice path using Call Disconnect  1818  message, leaving the called party and calling party on the voice path. If the calling party is not on hold, the NSP  106  can instruct the VAP  103 A to dial the last incoming call in the called party&#39;s record in memory  1240 . 
     According to another aspect of the UPCH feature, a mobile station user can in real time forward an unanswered incoming call to voice mail by entering a function code, for example by pressing “*2, SEND”. In this instance, an origination message with “*2” is sent upstream in the DCCH to the LDS  104 . The LDS  104  then routs the call to a VMS  107  coupled to the LDS  104 , where the calling party can leave a voice message. 
     Similarly, according to a further aspect of the UPCH feature, a mobile station user can in real time forward an unanswered incoming call to another DN or extension by entering a function code, for example by pressing “*3, and [the number of the forwarding location], SEND”. The id number of the forwarding location is transmitted upstream to the LDS  104  and NSP  106  which examines the id number to which the call is to be forwarded. If the id number matches a number in the system associated with LDS  104  or LDS  104 A, etc., the call is processed accordingly. Otherwise, the call is routed through, for example, the PSTN  125  to the appropriate end DN to receive the call. 
     According to another aspect of the UPCH feature, a mobile station user can in real time reject an unanswered incoming call by entering a function code representing a rejection key sequence, for example, “*4 SEND”. In response an origination message with “*4” is sent upstream to the LDS  104  and NSP  106  in the DCCH. A message indicating that the called party is not currently accepting calls may be issued by, for example, VPU  1235 , to advise the calling party. Alternatively, a tone may be transmitted from the LDS  104  to the calling party when the LDS  104  and/or NSP  106  detect a call reject flag. 
     According to still another aspect of the UPCH feature, a mobile station user can in real time create a short message and send it to the calling party of an unanswered incoming call by the called party entering a function code along with a message, for example, “*6, [a brief alphanumeric or voice message], SEND”. The short message travels upstream in the DCCH to the LDS  104  and NSP  106 , where it is transmitted downstream to the calling party. Voice synthesis in the VPU  1235  or DSP in the VAP  103  may be used to convert the alphanumeric message to a voice message. This feature may be particularly advantageous when the called party is busy and simply wants to communicate a brief real time message such as “Call you back in ten minutes” or “Meet me at home at 6:00”. 
     According to a further aspect of the UPCH feature, the called party can also chose to take no affirmative action so that a default action is implemented after a prescribed time period in the which the called party has failed to respond lapses. Default conditions may include, but are not limited to, forwarding the call to voice mail or letting the call go unanswered. The default condition for a particular subscriber is defined in the subscriber profile stored in memory  1240  of the NSP  106 . Thus, if the NSP  106  fails to receive any response from a called party, the NSP  106  will automatically process and terminate the call according to the called party&#39;s profile. 
     The UPCH service of the present invention can be integrated with an automatic call handling service, where based on certain criteria, a call can be handled automatically, and based on other criteria, a call can handled by the UPCH service. For example, a user may want all calls forwarded to voice mail from 10:00PM to 8:00AM and from 8:00AM to 10:00PM desire to process and terminate calls proactively. Also, a user may want all calls originating from certain IDs to be handled automatically while the remainder of the calls can be processed and terminated proactively. Further, a called party may desire to process and terminate calls proactively based on the physical location of the called party (e.g., office v. home). All this information can be defined and programmed in the called party&#39;s profile in the memory  1240  so that the NSP  106  knows how to route an incoming call properly according to a user&#39;s predefined or system default preference settings. 
     According to another illustrative embodiment of the invention, the NSP  106  can transmit a user alert, such as a tone, over the control channel to the called party to apprise the called party of an incoming call. A user alert can be incorporated with or without the SM application of UPCH described above. In response to the user alert, the called party can process and terminate the incoming call in real time as described above. Different tones can be assigned in the called party&#39;s profile in the memory  1240  so as to uniquely or specifically identify the calling party. 
     Further, the UPCH feature provides the ability to delay allocation of the voice channel to a called party until when, if at all, the incoming call to the called party requires a voice channel. This is carried out by allowing a called party to receive notification of an incoming call over the control channel and to return the selection of the call handling options upstream over the control channel. Thus, a voice channel need not be allocated until the called party decides to answer the call. This can be beneficial in wireless environments to prevent the unnecessary allocation of voice channels. Once the called party needs a voice channel, the incoming call has priority for available voice channels. 
     XII. Call Transfers 
     From time to time a telephone user, particularly a mobile phone MS  101  user, has need to transfer an active call to another telephone DN. Such situation arise when the other party needs to talk with someone else or would like to access a voice mail message in, for example, a VMS. In such instances the mobile station MS  101  user needs a quick, user friendly means to transfer the active call to another DN, i.e., the transfer-to DN (TransferDN). 
     The call tra nsfer feature/function allows the WCS MS  101  user to transfer an active call to another DN. The transfer-to DN can be either inside or outside the WCS network. The two exemplary embodiments provided below illustrate the call transfer feature/function where an active call is transferred from a WCS mobile station (e.g., MS  101 A) to another mobile station (e.g., MS  101 B) or to a PSTN telephone (e.g., PSTN  1215 ), respectively. 
     Referring to FIG. 19, a first preferred embodiment for the call transfer feature/function shows a call transferred by a mobile station MS  101  user from mobile station MS  101  to PSTN DN 2  ( 1215   b ) outside the WCS. Initially, it is assumed that a call between MS  101  and PSTN DN1 is in progress and the LDS  104  and VAP  103  identify this existing call as call reference  1  (Call in progress, CR=1  1900  shown as dashed lines at the top of FIG.  19 ). The MS  101  user may transfer an active call by entering a feature/function code for call transfer and digits associated with the DN to which the call is to be transferred. For example, the MS  101  user may enter on the MS  101  keypad the digits in the format of, for example, *77#TransferDN (the transfer-to DN is denoted as the TransferDN) and the “send” button. Each time a digit is pressed on the MS  101  a IS-136 Send Burst DTMF message is sent to the VAP  103  which in total is represented by the IS-136 Send Burst DTMF [*77#TransferDN]  1901  message, corresponding to all of the digits pressed. Then, by the MS  101  user pressing the “send” button, the MS  101  sends an IS-136 Flash With Info message to the VAP  103  indicating that the previously sent IS-136 Send Burst DTMF messages are complete and represent the end of the transmission representing a call transfer request. 
     Upon receiving each DTMF message from MS  101 , the VAP  103  sends an IS-136 Send Burst DTMF ACK  1902  message to the MS  101 . After receiving the Flash With Info  1903  message from MS  101 , VAP  103  sends a unique Feature Request message including the collected digits to the NSP  106 , e.g., Feature Request [*77#TransferDN]  1904  message. 
     When the NSP  106  receives the Feature Request [*77#TransferDN]  1904  message it identifies that the digits *77# is the feature code for the Call Transfer feature. Then the NSP  106  analyzes the feature code digits and validates via the WCSD in, for example, memory  1240 , whether MS  101  is authorized for the feature requested. If MS  101  is authorized to use the call transfer feature requested, the validation is successful and NSP  106  sends a Feature Request ACK [Play Voice Prompt (Transfer)]  1906  message to VAP  103  with the action as ‘Play Voice Prompt’ instructing VAP  103  to play an announcement/tone to the MS  101  user (and/or the PSTN DN1  1215   b ) indicating that a call transfer has been authorized (Voice Prompt  1907 ). Similar to the Call Hold feature/function procedure, the MS  101  and the PSTN DN1  1215   b  may be provided comfort noise by a digital signal process (DSP) to maintain continuity. However, if the validation of the Call Transfer feature/function request at NSP  106  is unsuccessful, the NSP  106  sends a Feature Request NACK (Not Acknowledged) message to VAP  103  prompting it to play an appropriate announcement/tone to the MS  101  indicating that the call transfer feature/function is not available and the call will not be transferred to the requested transfer-to DN (e.g., a Feature Request NACK [Play Voice Prompt (Transfer Not Allowed)] message is sent to VAP  103 ). 
     Once the call transfer has been authorized and the NSP  106  has sent a Feature Request ACK message to VAP  103 , the NSP  106  sends a unique Transfer message, Transfer [CR=1, TransferDN]  1908 , to the VAP  103  including the MSID of the requesting mobile station MS  101 , the VAP ID to which the message is directed, the call reference number (e.g., CR=1) and the transfer-to DN, TransferDN, to execute the call transfer procedure. The NSP  106  also starts the TCT 2  timer to ensure that the active call will not stay on hold indefinitely if for some reason the call is not properly transferred to the transfer-to DN. 
     In response to the Transfer [CR=1, TransferDN]  1908  message, the VAP  103  sends an information message, Q.931 Info [CR=1, Transfer]  1909 , to LDS  104  to request the call transfer for the current call (CR=1). In return, the LDS  104  sends a Q.932 Hold [CR=1]  1910  message to the VAP  103 . Then VAP  103  places the call on hold and sends a Q.932 Hold ACK [CR=1]  1911  message back to the LDS  104 . VAP  103  also sends a Q.931 Setup [CR=2, TransferDN]  1913  message having the call reference CR=2 and the transfer-to TransferDN to the LDS  104 . The LDS  104  initiates the ISUP connection to the TransferDN (PSTN DN2  1215   a  in the figure), and VAP  103  waits with the call on hold for the Q.931 Connect [CR=2]  1920  message from LDS  104 . 
     In establishing the call initiation with PSTN DN2  1215   a,  PSTN DN2  1215   a  (i.e., PSTN switch which services DN2) receives an ISUP IAM  1914  message from LDS  104  and VAP  103  receives a Q.931 Call Proceeding  1915  message from LDS  104 . In response, PSTN DN2  1215   a  send an ISUP ACM  1916  message to LDS  104  and LDS  104  provides a Q.931 Alerting  1917  message to VAP  103 . A Ringback Tone  1918  is provided to MS  101  so that the MS  101  user understand that the TransferDN is being alarmed as an incoming call. When PSTN DN2  1215   a  answers the call, an ISUP ANM  1919  message is sent to LDS  104 . The LDS  104  recognizes that the incoming call has been answered by the PSTN DN2 and sends the Q.931 Connect [CR=2]  1920  message to VAP  103 . 
     However, the MS  101  user can interrupt the call transfer before the called party at PSTN DN2  1212   a  answers (i.e., before the call is transferred), by for example pressing the send button on the MS  101  twice. In a situation when the MS  101  user is getting a busy signal or PSTN DN2  1215   a  is still ringing and the MS user presses the send button once, the message generated from the MS  101  will be ignored by the NSP  106 . However, if the MS  101  user presses the send button twice within a short period of time (e.g., a one-second period) and the call has not yet been answered by the PSTN DN2  1215   a  (the ISUP ANM  1919  message and Q.931 Connect [CR=2]  1920  message have not been generated), the NSP  106  identifies that the MS  101  is requesting to retrieve the held call and terminate the call transfer. Thus, in response the system will retrieve the original call (CR=1) and release the second call (CR=2). 
     Assuming that the MS  101  user does not interrupt the call transfer and the PSTN DN2  1212   a  answers, the PSTN DN2  1215   a  sends the ISUP ANM  1919  message to LDS  104  and the LDS  104  sends the Q.931 Connect [CR=2]  1920  message to the VAP  103 . When the VAP receives the Q.931 Connect [CR=2]  1920  message from the LDS  104 , it acknowledges connection with the PSTN DN2 and sends a Q.931 Connect ACK  1921  message back to LDS  104  and sends a Transfer Result [TransferDN, Answered]  1922  message to NSP  106  informing the NSP  106  that the TransferDN has answered. The unique Transfer Result message includes the MSID, VAP ID, Call Reference Number (e.g., CR=2), and Cause (e.g., success/fail). When the NSP  106  receives the unique Transfer Result [Transfer DN Answered]  1922  message from VAP  103  informing that the TransferDN has answered, the NSP  106  updates the call transfer status and cancels the TCT 2  timer. If the timer TCT 2  expires before receiving the Transfer Result  1922  message, the NSP  106  shall deactivate the Call Transfer feature by sending a Feature Request NACK message (not shown) in response to the Feature Request from VAP  103 . Then the VAP  103  shall send a Q.932 Retrieve [CR=1] message (not shown) to the LDS  104 , which retrieves the held call [CR=1] and sends a Q.932 Retrieve ACK back to the VAP  103 . 
     In the case that the Transfer Result [Transfer DN Answered]  1922  message is received by NSP  106  with the Transfer DN Answered message, if the MS  101  user now presses, for example, the “send” button once, an IS-136 Flash with Info  1923  message is sent to the VAP  103  to initiate completion of the call transfer (connecting call CR=1 from the PSTN DN1  1215   b  to the LDS  104  to the call CR=2 from the LDS  104  to the PSTN DN2  1215   a ). In response, the VAP  103  sends a Feature Request [FlashWithInfo]  1924  message to NSP  106  to request completion of the call transfer and send an IS-136 Flash with Info Ack  1925  message to MS  101  to acknowledge the call transfer completion request by the MS  101  user. Then NSP  106  determines that this is a call transfer completion action request, and sends a Feature Request ACK[Transfer (CR=2)]  1926  acknowledgment message back to VAP  103  indicating that the Call Reference to be transferred equals to 2 (CR=2). VAP  103  then requests LDS  104  to complete the call transfer by sending a Q.931 Info [CR=2, Transfer]  1928  message to LDS  104 , so that the LDS releases from the VAP  103  both call references (CR=1 and CR=2), the VAP  103  releases the RF to the MS, and the transferred call is left in progress between PSTN DN1  1215   b  and PSTN DN2  1215   a  (Transferred Call in progress  1937 ). 
     To release MS  101 , VAP  103  sends an IS-136 Release  1927  message to MS  101 . In response, MS  101  releases the voice channel air connection with VAP  103  and sends an IS-136 Mobile Ack  1930  acknowledgment message back to VAP  103  indicating that it has been released from the active call. To release VAP  103  from the active calls CR=1 and CR=2, LDS  104  sends a Q.931 Disconnect [CR=1]  1929  message and a Q.931 Disconnect [CR=2]  1933  message to VAP  103 . VAP  103  responds by sending a Q.931 Release [CR=1]  1931  message and a Q.931 Release [CR=2]  1934  message to LDS  104 . In return, LDS  104  sends a Q.931 Release Complete [CR=1]  1932  message and a Q.931 Release Complete [CR=2]  1935  message to VAP  103  to indicate that the LDS  104  has completed the call release process. 
     Once VAP  103  completes the Q.931 release procedures with LDS  104 , it sends a Transfer Complete [Success]  1936  message to NSP  106  to indicate to the NSP  106  that the call is no longer active with mobile station MS  101  in the WCS. The Transfer Complete message includes the MSID, the VAP ID, the call reference numbers (CR=1, CR=2), and a cause (success/fail) field. At this point the call transfer process has been completed successfully and the active call has been transferred from PSTN DN1  1215   b  and MS  101  to PSTN DN1  1215   b  and PSTN DN2  1215   a.    
     Referring to FIG. 20, a second preferred embodiment for the WCS call transfer feature/function shows a call transferred by a mobile station MS-1  101   a  user from mobile station MS-1  101   a  to another mobile station MS-2  101   b  within the WCS. In this embodiment, many of the signal flows in the call transfer process are the same as those in the first preferred embodiment for the call transfer feature/function and thus have the same number designations. The primary difference is the call setup procedure for setting up an incoming call to the second mobile station MS-2  101   b  and its related VAP, VAP 2   103   b,  as described below. 
     The signal flow to initiate call transfer of an active call in progress from one mobile station MS-1  101   a  to another mobile station MS-2  101   b  in the same WCS is the same as the signal flow to initiate call transfer from a mobile station MS  101  to a telephone, PSTN DN2  1215   a  outside the WCS. As such, from the point at which a mobile station (MS-1  101   a ) user involved in an active call in progress (Call in progress, CR=1,  1900 ) enters the call transfer feature/function activation code by pressing the digits in the format of *77# with the desired transfer-to DN, TransferDN, followed by the “send” button (results in the MS-1  101   a  sending an IS-136 Send Burst DTMF[77# TransferDN]  1901  message to VAP 1   103 ), up to the point when the active call is placed on hold (Call held, CR=1  1912 ) and the VAP 1   103   a  sends the Q.931 Setup [CR=2, TransferDN]  1913  message is sent to LDS  104 , the signal flows ( 1901 - 1913 ) are the same. Thus, in the second embodiment of the call transfer WCS feature/function of the invention, the call transfer is initiated by the MS, authorized by the NSP, and the active call is placed on hold (with appropriate prompt) awaiting further disposition by the WCS, for example, completed transfer of the held call to a second mobile station MS-2  101   b  as described below. 
     The Q.931 Setup [CR=2, TransferDN]  1913  message instructing LDS  104  to setup a second call with the transfer-to DN triggers an AIN query from LDS  104  to NSP  106  so that a TCAP (AIN Termination_Attempt [TransferDN])  2001  message is provided to NSP  106 . The NSP  106  verifies the location of the TransferDN within the WCS. Next, the MS-2  101   b  is paged with IS-136 Page Request  2002  message and the VAP 1   103   a  waits for the Q.931 Connect [CR=2]  1920  message from LDS  104  (after the LDS  104  receives Q.931 Call Proceeding and Alerting messages). While VAP 1   103   a  waits a voice channel connection with MS-2 is established as follows. 
     After MS-2  101   b  receives the IS-136 Page Request  2002  message, MS-2  101   b  send an IS-136 Page Response  2003  message to VAP 2   103   b  and VAP 2   103   b  sends Page Response  2004  message to NSP  106 . This triggers an AIN message, TCAP (AIN Forward_Call [VAP 2 -FDN], NEL [O_No-Answer])  2005 , sent by NSP  106  to LDS  104 . As a result, the NSP  106  has provided routing instructions that direct LDS  104  to forward the active call on hold to the Forward Directory Number (FDN) of VAP 2  (i.e., VAP 2 -FDN). NSP  106  has also indicated with this message its interest in event (O_No_Answer for VAP 2 -FDN) by sending next event list NEL [O_No_Answer]) information to LDS  104  in the Request component that accompanies the Routing component. 
     LDS  104  then starts a No Answer Timer (T(NoAnswer)) for VAP 2 -FDN (not shown) and sends an ISDN Q.931 Setup [CR=2, FDN]  2006  message to the VAP 2   103   b.  VAP 2   103   b  then sends a Digital Traffic Channel (DTC) Designation  2007  message to the MS-2  101   b  designating the traffic channel to be used and an ISDN Q.931 Call Proceeding  2009  message to the LDS  104  that triggers the Q.931 Call Proceeding  2010  message sent to VAP 1   103   a.  MS-2  101   b  then tunes to the traffic channel and responds to VAP 2   103   b  with an IS-136 Mobile on DTC  2008  message. VAP 2   103   b  detects that the MS  101  is on the appropriate traffic channel. VAP 2   103   b  then alerts MS-2  101   b  with an Alert-with-info  2011  message and MS-2  101   b  acknowledges with an IS-136 Mobile ACK  2015  message. VAP 2   103   b  also sends an ISDN Q.931 Alerting  2012  message to LDS  104  which triggers a Q.931 Alerting  2013  message to VAP 1   103   a.  Meanwhile, the LDS  104  is sending a Ringback Tone  2014  to MS-1  101   a  user. 
     When the MS-2  101   b  answers (before T(NoAnswer) timer expires) the MS-2  101   b  generates an IS-136 Connect  2016  message to the VAP 2   103   b  and the VAP 2   103   b  sends an ISDN Q.931 Connect message  2017  to the LDS  104  in response to the IS-136 Connect  2016  message from MS-2  101   b.  At this point the call transfer procedure continues the same as in the previous embodiment so that the MS-1  101   a  user can enter the appropriate key sequence to instruct the WCS to complete the call transfer process (steps  1920 - 1937 ). As a result, the active call in progress (CR=1) between PSTN  1215  and MS-1  101   a  is transferred so that the active call in progress is between PSTN  1215  and MS-2  101   b.    
     It should be appreciated that transferring a call from a mobile station in one WCS to a mobile station in another WCS could also be achieved by the NSP  106  providing the LDS  104  with routing instructions including a FDN indicative of a VAP  103  and MS  101  in the other WCS. Such a case could be achieved using a procedure similar to the procedure illustrated in FIGS. 19 and 20. 
     XIII. Caller ID 
     The Caller ID feature of the present invention allows display on the MS  101  of the originating directory number for the calling party&#39;s desk top telephone (Calling Party Number, DN O ) and identity (e.g., name) for an incoming and/or active call, even if the call originates from another MS  101 . Further, the Caller ID information may include location information, e.g., building number, derived from the forward directory number (FDN) of the originating VAP  103  (VAP O ). In addition, the Caller ID feature of the present invention may provide the location and identity of the called MS  101  to the calling party and displayed on the calling party&#39;s MS  101  during an active call. In either case, a Network Server Platform (NSP)  106  provides a MS  101  user&#39;s desk top phone directory number, DN O , as their telephone number for Caller ID rather than the forward directory number (FDN) associated with an originating VAP  103 , VAP O    103 , with which the MS  101  is currently associated. 
     The caller ID or the calling party identification is the number associated with the phone from which the call is originating. The WCS Caller ID feature allows the calling party&#39;s phone number, identify, and related information to be displayed on the WCS mobile handset, MS  101 . 
     Caller ID for a call originating from a PSTN  125  to an MS  101  in a WCS will occur much the same way that caller ID occurs entirely within a PSTN  125 . The WCS Caller ID feature will present to the MS  101  in the WCS environment all the information that the PSTN  125  passes to the VAP  103 , e.g., calling party telephone number and calling party name. However, if the PSTN  125  does not pass this info to the VAP  103 , (e.g., caller id blocking), the VAP  103  can not, and does not, present any calling party information to the MS  101 . 
     Caller ID for a call originating from a WCS MS  101  is different than caller ID for a call originating from a PSTN  125  because the MS  101  is wireless and is associated with the forward directory number of a VAP  103 , rather than the directory number (DN) of a stationary telephone. Due to the wireless nature of the MS  101  and its association with a VAP  103  (or a number of different VAPs) in a WCS, Caller ID for calls originating from an MS  101  in a WCS requires unique treatment in order to provide a calling party telephone number and name which is recognizable. In the case that the WCS user has both a desk top telephone and a MS  101 , the problem may be solved by the NSP  106  providing the users desk top telephone DN for Caller ID purposes, regardless of what VAP  103  the MS  101  is associated with at any point in time. Alternatively, if the MS  101  user does not have a desk top telephone within the WCS the NSP  106  may be programmed to provide any telephone number, for example the MS  101  user&#39;s home number, the business main number, or the FDN of the VAP  103  to which the MS  101  is currently associated. Although the Caller ID feature/function of the present invention will be described with respect to a call between one MS  101  and another MS  101  having the same NSP  106 , one skilled in the art will recognize that Caller ID for an MS  101  originating a call may similar be provided if the mobile stations  101  have different NSPs  106  which can communicate so as to pass the Caller ID information to one another. 
     The preferred embodiments of the WCS Caller ID feature/function provides calling party information to the called party (e.g., phone number, name, address, building number, etc.) for a call between two WCS users, e.g., an originating mobile station, MS O    101 , and a terminating mobile station, MS T    101 . This intelligence is managed by the NSP  106  and thus also enables called party information to be provided to the calling party, e.g., location of the called party. Three preferred embodiments are provided below: (1) the intelligence of the NSP  106  is used to correlate originating and terminating call legs of a call and sends the appropriate caller ID information; (2) an information element in the call control message, such as the Q.931 Calling Party Subaddress information element of the Setup message, is used to provide caller ID information; and (3) a signaling protocol that supports non-call associated temporary signaling for user to user data transfer, e.g., the Q.931 User Information message, is used to provide caller ID information. These embodiments are merely exemplary. 
     Providing the Caller ID features/functions for WCS to WCS calls can be simplified into two general tasks. First, the NSP  106  must be updated with the originating party information of every call that originates from a WCS MS  101 . This can be done during the call origination and hence we categorize these tasks as being included in the call origination leg. To provide the terminating VAP, VAP T    103  with this information (the Caller ID information). These tasks can be categorized as the one that must be performed during the call termination leg. 
     A first preferred embodiment will now be described with reference to FIGS. 21A-21D. This embodiment depends on the intelligence of the NSP  106  to provide the correct Caller ID information. For a WCS (e.g., MS O    101 ) to WCS (e.g., MS T    101 ) call, the NSP  106  must perform the following two functions. First, the NSP  106  maintains originating party information of every originating call that terminates to a WCS user. Second, for every incoming call, the NSP  106  correlates the terminating leg of the call with the corresponding originating leg so as to retrieve the originating party information and pass this information to the terminating VAP T    103  to be provided to the terminating MS T    101 . These functions require the NSP  106  to track the originating calls and match them to the correct terminating portion of the call. 
     As indicated above, providing caller ID information for this preferred embodiment splits the processing in two legs—the origination request (leg) and the termination request (leg). The information regarding the caller of each call originated is recorded at the NSP  106  and during the termination of any call (in this case within the WCS); the caller id related information is extracted based on the calling VAP&#39;s  103  FDN. 
     Referring now to FIG. 21A, a flowchart for caller ID information retrieval procedure is provided and shows the origination leg of the WCS Caller ID feature/function according to a first preferred embodiment. When a call originates from a WCS subscriber&#39;s originating MS O    101  to another WCS subscriber&#39;s terminating MS T    101  (for simplicity, both MS O    101  and MS T    101  are served by the same NSP  106 ), as a first step in the origination leg, step  2101 , the MS O    101  originates a call to MS T    101 . Next, at step  2102  the VAP  103  will send the WCS origination request, which will contain the FDN associated with the serving VAP  103  to the NSP  106 , along with the originating MS O    101  id, i.e. MSID. Then, at step  2103 , the NSP  106  uses the MSID to determine whether the WCS user (MS O    101 ) is registered within the WCS. If not, the NSP  106  rejects the MS origination at step  2104 . If the MS O    101  is registered with the WCS the NSP at step  2105  determines if the MS O    101  has called (requested) a WCS number as the terminating number DN T . If not, the NSP  106  follows the normal call processing at step  2107  and sends an origination ack message. However, if the NSP  106  determines that the called termination number DN T  is within the WCS, the NSP extracts the DN O , i.e. the DN of the desktop associated with the MSID of the originating MS O    101  and records the originating user information along with the DN T , at step  2106 , in a Caller ID table. This mapping between the MSID and the corresponding DN can be found in the subscriber information in the WCS database (WCSD). Thus, the NSP  106  in step  2106  stores the DN O  and the FDN information against the DN T , i.e. the DN of the phone where the call has to terminate, in a record and subsequently continues the normal call processing by, for example, sending an origination acknowledgement message in step  2107 . 
     Referring now to FIG. 21B, when the call comes to the termination leg the LDS  104  at step  2108  sends, for example, an AIN TAT message to the NSP  106  which includes, for example, the DN T  and the FDN of the originating VAP, VAP O    103 , information in it. Next, in step  2109 , the NSP  106  checks to determine that the Caller ID table in the WCSD has an entry for the DN T  which matches the originating FDN. If there is a match of the DN T  and the FDN, the NSP  106  retrieves the caller ID information, for example, the desktop telephone directory number DN O  for the originating mobile station, MS O    101 , and sends it to the termination VAP, VAP T    103 , in, for example, a page request message, as shown at step  2110 . Then, the caller ID information, for example, DN O , may be sent by the VAP T    103  to the MS T    101  in, for example, an IS-136 Alert with Info message. As a result, the MS T    101  will display the caller ID information, for example the DN O , on the MS T    101 . 
     On the other hand, if at step  2109 , the NSP  106  does not find a caller ID match for the DN T  with the originating FDN or there is no specified DN O  within the database for MS O    101 , the NSP  106  sends, for example, a page request message to the terminating VAP T    103  without a DN O . Then, at step  2113 , the VAP T    103  sends the calling party number contained in, for example, a Q.931 Setup message, which may be the FDN of the originating VAP. It should be noted that the DN O  related information can be stored at the NSP  106 , and can be used for the other features like call return, call screen etc for this call. 
     Clearing of the calling party number related information records from the NSP  106  may be handled as follows. The caller id related records are created during the call origination and may be cleared off during call termination. Certain information may be required to be updated at the NSP  106  before the caller id related record is cleared. For instance, the “last calling party number” is needed for call return feature; hence a field holding this value shall be updated. The caller id record for a call may be cleared from the NSP  106 , if any of the following occur: (1) when NSP  106  has paged the MS  101  with the DN O  information, (2) when a call fails during the origination attempt, (3) when the call is delivered to the desktop phone, and (4) when the call is treated as the waiting call in case of the call-waiting feature (that is, when NSP  106  notifies VAP  103  of call waiting. Furthermore, all the records may include a time stamp of the time when they are created, and the WCS may include periodic checking for the time stamps which are older than a certain amount of time, which if found, such records would be automatically and periodically cleared. Referring to FIGS. 21C and 21D, exemplary signal flow diagrams are provided for a call origination and termination within the WCS for the first preferred embodiment of the Caller ID feature/function. As indicated by the flowcharts in FIGS. 21A and 21B, implementation of the Caller ID feature/function in this embodiment requires some additional things be done beyond the normal signal messages exchanges between VAP  103 , NSP  106  and LDS  104 . 
     An exemplary signal flow for the call origination leg of the first preferred embodiment for the Caller ID feature/function is illustrated in FIG.  21 C. During call origination the originating WCS MS, MS O    101 , requests for the call origination by sending an IS-136 Origination  2114  message including an MSID to the VAP O    103  followed by optionally an IS-136 Serial Number message  2115  which includes the electronic serial number (ESN) of the MS O    101 . Then VAP O    103  sends an Origination Request  2116  message to the NSP  106 . The Origination Request  2116  message contains the Called party id i.e., DN T , the FDN of the originating VAP O    103 , and the identification of the originating MS O    101  MSID and/or the ESN. The NSP  106  validates the originating MS O    101  and checks whether the termination directory number, DN T  is a WCS subscriber. If it is, then NSP  106  searches the WCSD for a DN O  of the MS O    101  associated with the MSID and, if one exists, extracts and records the DN O  of the MSID as being correlated to the destination (termination) DN, DN T , as indicated in step  2117 . In other words, the NSP  106  retrieves the DN associated with the originating MSID, e.g., the DN O , and records the FDN and the DN O  against the called party DN, e.g., DN T . Next, the NSP  106  sends the Origination Ack  2118  message. Subsequently, signaling  2119 - 2127 , illustrate normal Call processing to completion of a voice path between the MS O  and the MS T  ( 2128 ). Thus, the signal flow for signaling  2119 - 2127  is similar to the usual origination call flow as described in the call processing section above (see, for example, FIG.  4  and its related description). 
     Referring now to FIG. 21D, an exemplary signal flow for the call termination leg of the first preferred embodiment for the Caller ID feature/function is illustrated. First, since in this case the incoming call is from another MS, MS O    101 , within the WCS, a Q.931 setup message (triggered by, for example, Q.931 setup  2119  message) is received by the LDS  104  (not shown in figures). Alternatively, if the incoming call is from PSTN  125  an ISUP IAM message will be received by the LDS  104 . In either case, the LDS  104  recognizes the incoming call as being directed to an MS  101  and thus sends an AIN TAT message, TCAP (AIN Termination_Attempt [DN T , FDN])  2129 , to the NSP  106  so that the NSP  106  can provide information to the LDS  104  regarding the present location of the MS  101  associated with the termination directory number, DN T , so as to properly route the call. As illustrated, the AIN TAT message will contain the DN T , i.e., the called party ID, and the calling party number, which is the FDN of the originating VAP O    104  in the case where the call originates within the WCS. 
     Next, the NSP  106  attempts to match the originating terminal id, in this case the FDN of the originating VAP O    103  for this AIN TAT message, against the FDN, DN T  pairs stored within its records (during the call origination leg). If there is a record with a matching FDN for the designated DN T , the NSP  106  will extract the previously stored caller ID information, for example DN O , from the WCSD and send it to the termination VAP, VAP T    103 , in a Page Request [MSID, DN O ]  2131  message. If no match is found, then DN O  shall not be populated and the VAP T    103  shall receive the calling party number provided in the Q.931 setup message (e.g., a PSTN  125  DN or a VAP  103  FDN). In essence, if there are no records with matching FDN, then there is no special information sent to the VAP T    103  in the Page Request  2131  message and VAP T    103  will present the calling party number information it gets from the Q.931 messages to the MS T    101 . In any case, the usual call processing procedures follows at steps  2131 - 2141 . 
     Then at step  2141 , the VAP T    103  sends the caller ID information to the MS T    101  to, for example, display the caller ID information to the MS T    101  user. In the case there is a match, the VAP T    103  sends an IS-136 Alert with Info [DN O ]  2141  message to the MS T  with, for example, the DN O  information and/or other caller ID information (from Page Request  2131  message or the Q.931 setup message) to provide the MS T    101  user with the caller ID information, which in the case is the caller ID information for the originating MS O    101  user (e.g., the DN O  of the MS O    101  user&#39;s desk top telephone). If there is no match, the VAP T    103  sends an IS-136 Alert-with-Info  2141  message to the MS T    101  with the calling party number value from the Q.931 Setup  2137  message. Subsequently, at steps  2142 - 2150 , the call processing for the Caller ID termination leg for this embodiment is similar or the same as those mentioned for a general call termination in the call processing section above (see, for example, FIGS. 5-7 and their related description). 
     A second preferred embodiment for the Caller ID feature/function will now be described with reference to FIGS. 21E-21H. This embodiment does not depend on the intelligence of the NSP  106  to provide the correct Caller ID information. Once again, this embodiment also splits the processing in two legs—the origination request (leg) and the termination request (leg). In this case the WCS relies on existing signaling protocol to forward the caller ID information without storing and subsequently matching the data in the WCSD for the originating VAP O    103  FDN and the termination MS T    101 . 
     In this preferred embodiment, the caller ID information regarding the caller of each call originated (e.g., the DN O  associated with the originating MS O    101 ) is sent by the NSP  106  to the originating VAP O    103  in, for example, the Origination Ack. The NSP  106  does not set up a record in the WCSD but merely extracts the caller ID information, for example the DN O , from the WCSD and sends it to the originating VAP O    103 . The VAP O    103  then sends the calling party caller ID information (e.g., DN O ) in an available field of an existing message sent to the LDS  104 , for example, the subaddress IE of its Q.931 Setup message sent to the LDS  104 . Subsequently, during the termination leg, the LDS  104  preserves and forwards this caller ID information to the terminating VAP T    103  in an existing call setup message, for example, in the subaddress IE of a Q.931 setup message that the LDS  104  sends to the terminating VAP T    103 . This information can now be presented by the terminating VAP T    103  to the terminating MS T    101  through an existing call setup message, for example, an Alert with Info message. This general method of the second preferred embodiment is described in more detail below. 
     Thus, this approach is dependent on the ability of using an information element field of a call control message passed from the originating VAP O    103  to the destination VAP T    103 . An example of this is the Q.931 Calling Party Subaddress field of the Q.931 Setup message. This field can be use to carry caller ID information regarding the calling party, such as the DN of the desktop phone associated with the originating MS, caller&#39;s name, caller&#39;s address, caller&#39;s location, etc. 
     Referring to the flowchart in FIG. 21E, the process for the origination leg of the second preferred embodiment of the Caller ID feature/function is illustrated and will now be described. Once again, the embodiment illustrates a scenario for a call originating from a WCS subscriber&#39;s MS, the originating MS O    101 , to another WCS subscriber, termination MS T    101 . First, at step  2151 , the user of an MS  101  originates a call. Then, at step  2152 , the VAP  103  sends a message to the NSP  106 , for example, a WCS origination request message, which may contain the originating phone&#39;s ID, i.e. MSID, and the called party number, e.g., DN T . Next, at step  2153 , the NSP  106  determines whether the MS  101  user is registered with the WCS. If the MS  101  is registered and valid, in step  2155  the NSP  106  retrieves the caller ID information, e.g., DN O  (the DN of the desktop associated with the MSID) by accessing the mapping between the MSID and the corresponding DN which may be stored in, for example, the subscriber information in WCSD. The NSP  106  also forwards the caller ID information (e.g., DN O ) to the VAP  103  in a typical call setup message, for example, an origination ack message. Then in step  2156 , the originating VAP O    103  sends the caller ID information (e.g., DN O ) to the LDS  104  in an available field of another typical call setup message, for example, the subaddress IE field of a Q.931 Setup message. However, if the MS O    101  is not a registered user, the NSP  106  will reject the origination message at step  2154 . 
     Referring now to the flowchart in FIG. 21F, the process for the termination leg of the second preferred embodiment of the Caller ID feature/function is illustrated and will now be described. First, in step  2157  the LDS  104  sends a typical call setup message, for example an AIN TAT message, to the NSP  106  so as to terminate the call at the DN T  originated by the DN O . At step  2158  the NSP  106  responds by sending a typical call setup message to the VAP T    103  to which the termination MS T    101  is presently associated, for example a Page Request message. The VAP T    103  responds by sending a typical call setup message indicating that the desired MS T    101  is available via a Page Response message The NSP  106  instructs the LDS  104  to forward the incoming call to VAP T    103  using, for example, an AIN Forward_Call message. At step  2159 , the LDS  104  sends a typical call setup message to the terminating VAP T    103 , for example a Q.931 Setup message. Since the originating VAP O    103  put the caller ID related info (e.g., DN O ) in the subaddress IE of the Q.931 SETUP message, this info will be contained in, for example, the subaddress IE of the Q.931 SETUP sent from the LDS  104  to the terminating VAP T    103 . As indicated at step  2160 , if the subaddress IE field is populated with caller ID information, for example DN O  for the calling MS  101 , the VAP T    103  will receive the information and provide it to the MS T    101  via a typical call setup message, for example an IS-136 “Alert with Info” message. Otherwise, the VAP T    103  shall use the Calling party number information, e.g., the VAP O    103  FDN or the PSTN  125  DN from the Q.931 SETUP message. 
     Referring now to FIG. 21G a detailed signal flow diagram for an origination leg of the second preferred embodiment of the Caller ID feature/function will now be described. First, an originating WCS MS, MS O    101 , requests for call origination by sending an IS-136 Origination  2161  message and an optional IS-136 Serial Number  2162  message containing the ESN to the originating VAP O    103 . Then, the originating VAP O    103  sends an Origination Request [MSID, DN T ]  2163  message to the NSP  106 . The Origination Request message contains the Called party ID, DN T , FDN of VAP O  and the identification of the originating MS O    101 , MSID and/or the ESN. Next, the NSP  106  validates the MS O , and retrieves the caller ID information, for example a DN O , associated with the MSID. The NSP  106  sends the caller ID information, e.g., DN O , to VAP O    103  in an available field of the Origination Ack [DN O ]  2165  message. 
     Then the VAP O    103  sends the caller ID information, e.g., DN O , that it received from the NSP  106  in the Calling Party Subaddress IE of the Q.931 Setup [Subaddress IE=DN O  info]  2166  message that it sends to the LDS  104 . The LDS  104  will setup the call to DN T  (this will trigger an AIN message in the terminating leg signal flow (see FIG.  21 H)). Subsequently, signaling  2167 - 2174 , illustrate normal call processing to completion of a voice path between the MS O  and the MS T  ( 2175 ). Thus, the signal flow for signaling  2167 - 2174  is similar to the usual origination call flow as described in the call processing section above (see, for example, FIG.  4  and its related description). 
     Referring now to FIG. 21H, the signal flow for the terminating portion of an exemplary second preferred embodiment for a WCS MS to WCS MS call will be described. As indicated above, the originating MS O    101  user calls another WCS MS  101  subscriber&#39;s DN, the terminating DN T , and as a result the LDS  104  receives a Q.931 Setup [subaddress IE=DN O  info]  2166  message. The LDS  104  finds that the DN T  is provisioned for AIN Termination Attempt Trigger (TAT). As a result, the LDS  104  suspends the delivery of the call and sends an AIN query message, TCAP (AIN Termination_Attempt [DN T , FDN])  2176 , to the NSP  106  for appropriate routing instruction based on the last known location of MS T    101 . NSP  106  finds that the subscriber&#39;s MS  101  (MS T ) associated with DN T  is active and idle in its serving area, associated with VAP T    103 . NSP  106  pages the MS T    101  through VAP T    103  with IS-136 established paging procedures, e.g., Page Request [MSID]  2178  and IS-136 Page  2179 , and starts TT 6  timer. As a part of the Page Request  2178  message, the NSP  106  shall send the Mobile&#39;s MSID. MS T    101  sends an IS-136 Page Response  2180  message followed optionally by IS-136 Serial Number  2181  message. When MS T    101  responds to the page, VAP T    103  selects a FDN for the call, and forwards it in a Page Response [FDN]  2182  message to the NSP  106 , and starts event timer TT 10 . Upon reception of Page Response [FDN]  2182 , the NSP  106  will cancel TT 6  timer and knows that the current VAP T    103  has the resources to serve the incoming call. 
     Next, the NSP  106  directs the LDS  104  to forward the call to the FDN (in a TCAP Conversation package) by sending the LDS  104  a TCAP (AIN Forward_Call [FDN], NEL [O_No_Answer])  2183  message. The NSP  106  indicates its interest in event (O_No_Answer for FDN) by sending next event list (NEL) information to the LDS  104  in a Request component, which accompanies the routing component, in the conversation package. The LDS  104  will start No Answer Timer (T(NoAnswer)) for FDN and send a Q.931 Setup [FDN, Subaddress IE=DN O ]  2184  message to VAP T    103 . When VAP T    103  receives the Q.931 Setup [FDN, Subaddress IE=DN O ]  2184  message, it will cancel the TT 5  timer, initiate an IS-136 DTC Designation  2185  message to MS T    101 , start the TT 2  timer, and send a Q.931 Call Proceeding  2186  message to the LDS  104 . VAP T    103  will retrieve the calling party information first from Q.931 Calling Party Subaddress IE indicating that this call is from a WCS MS (refer to the Q.931 Setup [FDN, Subaddress IE=DN O ]  2166  message in the originating call leg signal flow shown in FIG.  21 G). If the subaddress is not populated then VAP T    103  will attempt to retrieve the calling party information from the Q.931 Calling Party IE indicating that this call is from the PSTN  125  or a VAP  103  FDN. If neither fields are populated, the calling party information can not be retrieved and therefore can not be presented to the called party. 
     Next, the VAP T    103  sends a DTC Designation  2185  message to the MS T    101  and the MS T    101  tunes to the traffic channel, MS on DTC  2187 . When VAP T    103  detects that MS T  is on the traffic channel via DVCC status change, it will initiate the Alerting procedures to both call legs (i.e., the LDS and MS directions). Then VAP T    103  sends an IS-136 Alert-with-info message to MS T    101  along with the retrieved calling party caller ID information (if any) for example IS-136 Alert-with-info [DN O ]  2188  message, and start the Alert timer (TT 3 ). When MS T    101  receives the Alert-with-info message, it may notify the user with an alert, e.g., via ringing. MS T    101  then sends an IS-136 Mobile ACK  2189  message to the VAP T    103 . When VAP T    103  receives the Mobile ACK  2189  from MS T    101 , it will cancel TT 3  timer and start TT 4  timer, and enters the wait-for-answer call processing state. Subsequently, at steps  2190 - 2197 , the call processing for the Caller ID termination leg for this embodiment is similar or the same as those mentioned for a general call termination in the call processing section above (see, for example, FIGS. 5-7 and their related description). 
     A third preferred embodiment for the WCS Caller ID feature/function is similar to the second preferred embodiment and uses existing signaling messages to coordinate the caller ID information. This preferred embodiment is dependent on a signaling protocol that permits exchange of user to user data. For example, in addition to the normal call setup procedure described above, the originating VAP O    103  uses the Q.931 non-call associated signaling procedure to send the calling party information to the destination (termination) VAP T    103  before the destination VAP T    103  sends the IS-136 Alert-with-Info message. Thus, in this embodiment it is not necessary to use the Calling Address Subaddress IE field. 
     The WCS Caller ID feature/function invention may provide caller ID information whether the call is from one MS  101  to another MS  101  associated with the same NSP  106  or different NSPs. In the case of different NSPs, the process must include a means of transferring or sharing of the caller ID information, e.g., DN O  between the various NSPs. Further, the WCS MS  101  caller ID information may also be provided to a call to a PSTN  125  user as long as a means is provided for entering the caller ID information related to the MS  101  DN O  into the signaling between the PSTN  125  and the WCS. 
     Further, the WCS Caller ID feature/function of the present invention may provide for the calling party to be initially coupled with a voice path to, for example, a voice processing unit (VPU) including voice recognition capabilities, which is located in, for example, the VAP  103 . As such, the calling party can provide their name or other information which will be provided to the called party, by for example, display on the MS of the called party. The Caller ID feature/function may also allow display on the MS  101  or audio presentation of additional information about the calling or called party, for example their address, building number, company affiliation, etc. for an incoming or active call. Thus, the WCS of the present invention provides a MS  101  user with the ability to know the identity of the calling persons before answering a call and the desk top telephone number, identity, location, etc. of a calling party or a party they are speaking with on an active call, even in the case when the calling party is calling from a WCS MS. 
     XIV. Screening Calls 
     The advent of any time and any place communications provided by the present invention brings with it certain conveniences and certain inconveniences or annoyances. Ideally, the invention should minimize the inconveniences or annoyances. One inconvenience is that anyone, for example a solicitor, can call a mobile station at anytime, for example in the middle of an important meeting. Therefore, there is a need to provide the mobile station user in a WCS the ability to block out incoming calls from particular phone numbers, for example, directory numbers. 
     The call screening feature/function of the instant invention provides just such a means for screening calls in a Wireless Centrex Services (WCS) System. More specifically, the invention allows a mobile station user to specify a list of phone numbers (call screen list) from which incoming calls can be blocked when received. When any one of the phone numbers in the list is calling the MS  101 , based on the MS  101  user&#39;s previous instructions the WCS system will block the call and either send the call to a message answering service (e.g., a VMS  107 ), send the call to intelligent peripheral (IP) device (e.g., a VPU  1235  or a DSP) which will provide a pre-recorded announcement message, or just simply drop the call without providing the calling party any announcement or recourse. 
     The call screen list of phone numbers can be added to or modified using a number of different methods. In one exemplary embodiment, a MS user enters the phone number manually from the MS  101  by keying in each digit of the phone number to be blocked. The MS  101  user dials a feature activation code, for example, *60#, followed by the phone number that is to receive the call screening treatment, followed by the send button (e.g., *60#5551212). In response, the WCS system adds the phone number (e.g., 5551212) to the Call Screen list and activates the call screen feature for the phone number entered. This confirms the feature activation. 
     In another exemplary embodiment of the call screen feature/function of the invention, the call screen list can be added to or modified by pressing a particular key on the MS  101  or by entering the feature code without a phone number, after an active call is disconnected (e.g., after an unwanted incoming call is received). In this case, as an example, the user can key in the feature code, e.g., *60#, on the MS  101  and press the send button after a call is hung up. The WCS will retrieve the last active call&#39;s related phone number from its database and add it to the call screen list for the MS. 
     In either of the previous embodiments, a MS user can remove a particular phone number from the Call Screen list or turn off the call screen feature by, for example, pressing a button on the MS  101  or keying into the MS  101  a particular feature code, with or without a phone number to be removed from the Call Screen list. For example, a MS user may key into the MS  100  a Call Screen feature deactivation code, for example *600#, and the phone number and press the send button. As a result an incoming call to that particular phone number will no longer receive call screen treatment. Alternatively, if the MS  101  user enters a Call Screen feature deactivation code, for example *600#, without entering along with it a phone number, all call screen treatment will be deactivated for all phone numbers on the Call Screen list. 
     In yet another embodiment for the call screen feature/function of the invention, the Call Screen list can be added/modified via the internet (World Wide Web) or by calling the WCS CSC representative. A more detailed discussion of the call screen feature/function of the present invention follows. 
     Referring to FIG. 22, a signal flow for provisioning (activating) the call screen feature/function will now be discussed using the embodiment wherein the MS  101  user enters a feature code and phone number via the MS  101  to activate call screening to block an incoming call. In general, the signal flow for provisioning the call screen feature may follow the methods discussed previously for feature activation. First, the MS  101  user enters the feature activation code and number on the keypad of an MS  101 , such as, *60# CallScreenDN, where CallScreenDN is the desired directory number (i.e., phone number) to be screened out (i.e., the MS  101  user will not know about the call at the time the incoming call occurs). As a result an IS-136 Origination [*60# CallScreenDN]  2201  message is sent from the MS  101  to the VAP  103  over the Reverse Digital Control Channel (RDCCH) wherein the called party number field is set to CallScreenDN. The VAP  104  receives the IS-136 Origination [*60# CallScreenDN]  2201  message and sends an Origination Request [*60# CallScreenDN]  2202  message to the NSP  106  and starts the origination complete timer TO 1 . The Origination Request [*60# CallScreenDN]  2202  is unique in that the Dialed Digit IE (field) which normally contains a DN the MS  101  user wishes to connect to, now contains the feature code *60# and the incoming DN to be screened, CallScreenDN. 
     The NSP  106  receives the Origination Request [*60# CallScreenDN]  2202  message, performs an analysis of the dialed digits and determines that it is actually a feature request, i.e., a Call Screen request, rather than a telephone call. Next the NSP  106  proceeds to check against the service profile in the WCSD (stored in, for example, the memory  1240 ) via the MIN of the MS  101  to determine whether the MS  101  is authorized for the Call Screen feature. If the validation is successful the NSP  106  updates the feature activation table for the particular MIN and sends a call origination not acknowledged message, Origination NACK [Cause, Display]  2203  to the VAP  103  which includes proper text information pertaining to the feature, e.g., Call Screen active and the number of the DN that is programmed to be screened. Alternatively, the information contained in this message could be provided via a short message format such as an SMDPP message (similar to an IS-41 message). Next, the VAP  103  sends an IS-136 Reorder/Intercept [Display]  2204  message to the MS  101 . This message contains status information regarding the MS  101  user&#39;s request to block a call with the call screen feature/function. For example, the Display information may contain the statement “Call Screen active for CallScreenDN. Similar to the Origination NACK message, the IS-136 Reorder/Intercept message is generated as a result of a telephone call setup is rejected because the numbers dialed by the MS  101  user to activate the call screen were not a recognizable DN for which a telephone call could be established. Thus, the Display field of this message is modified to carry the information to indicate to the MS  101  user the status of their call screen request. 
     On the other hand, if the NSP  106  determines that the MS  101  is not authorized to use the Call Screen feature, it will send a message Origination NACK [Cause, Display]  2203  message with proper reject information in the cause (e.g., text) field (Call Screen Not Available) to the MS  101 . After receiving the Origination Request message  2203  from the VAP  103  to the NSP  106 , an Origination NACK message will be sent to the VAP  103  and the VAP  103  will then cancel the timer TO 1 , release the MS  101 , and clear the origination request record. 
     As previously indicated, if the MS  101  user does not enter a CallScreenDN at the time of initiating the call screen feature, then the WCS will determine the DN for the last active call to which the MS  101  was a party, and activate a call screen for that particular DN. In the case when the DN is not specified and the last active call was an incoming call, the NSP  106  will use the last incoming Caller ID to activate call screening. If the last caller ID is available, the NSP  106  updates the feature activation table for the particular MIN and sends a n Origination NACK [Cause, CallScreenDN]  2203  message with proper text and the CallScreenDN information to inform the MS that calls from the identified CallScreenDn will be screened. Otherwise, if a Caller ID for the previous active call can not be determined the NSP  106  will notify the VAP and MS  101  that the call screen feature has not been activated. 
     The call screen feature/function also includes a feature that allows the MS  101  user to determine the disposition of an incoming call which is blocked because the incoming call DN is included in the Call Screen phone number list. The MS  101  user can pre-program the WCS by entering a feature programming code associated with a particular manner for the WCS to handle an incoming call after it is blocked by a call screen designation (i.e., call screen treatment). For example, the MS  101  user can provision the DNs that he would like to screen and the manner in which the call coming from a CallScreenDN may be treated by manually entering particular feature/function codes on the MS  101 . The provisioning can also be done through the WCS web site or by calling a Customer Service Center (CSC) representative. Below are illustrations of methods by which the MS  101  user can pre-program the CallScreenDN list by himself/herself using the MS  101 . The exemplary provisioning mechanism are as follows. 
     To provision the. Call Screening list, the MS  101  user may dial for example *60#n#DN, where n is a number between 1 and 3 and signifies the call screen treatment, and DN is the CallScreenDN telephone number, then press the “send” button (e.g. *60#1#5551212). The correspondence between three possible call screen treatment codes and the treatment to be executed is provided in the table below. 
     
       
         
           
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 Code 
                 Treatment description 
               
               
                   
               
             
            
               
                 1 
                 Disconnect the call 
               
               
                 2 
                 Forward the call to the specified resource (e.g., VMS) or DN 
               
               
                 3 
                 Play voice announcement that “called party unavailable” 
               
               
                   
               
            
           
         
       
     
     Alternatively a desired CallScreenDN can be dynamically added to the list of CallScreenDNs after an unwanted call is received. The MS  101  user can press *60#n and the “send” button during or immediately after an active call is released. In response, the WCS will retrieve the calling party number and add it to the call screen list for the MS  101 . If no number is specified to indicate the type of call screen treatment desired (e.g., 1, 2, or 3) while provisioning (e.g., *60##DN) a default will be set, for example, the type 1 call screen treatment will be provided for calls coming from the entered CallScreenDN (DN input with the feature code *60). Further, to remove a particular phone number from the list, the MS  101  user may dial for example *600#DN, where DN is the CallScreenDN telephone number, and press the “send” button. To remove all the entries from the table, the user may press, for example, *600# *. 
     Thus, the user of MS  101  can enter a feature programming code, for example, *601# with a phone number being screened, CallScreenDN, and press, for example, the send button to program the incoming call to be dropped without any announcement to the calling party. This feature programming code would be stored in the WCSD and be associated with the CallScreenDN to which it relates. The signal flow for this added feature programming would be similar to the signal flow for Call Screen feature activation illustrated in FIG.  22 . If the MS  101  completes such Call Screen feature programming by entering *601#, when an incoming call originates from the CallScreenDN phone number, the WCS will drop the blocked call without playing any announcement. 
     Different feature programming codes, for example, *602#, *603#, etc., could be used to program the WCS to dispose of a call screen blocked call by sending it to a VMS  107  or playing an announcement to the calling party indicating that the call is being blocked, etc. Further, the WCS can be programmed so that any one of these call screen treatments (as well as any other not mentioned herein) is used as the default Call Screen blocked call disposition. A detailed discussion of the signal flow for some of the possible disposition of incoming calls blocked by the Call Screen feature follows. 
     In accordance with one preferred embodiment of the invention, FIG. 23 illustrates an exemplary call screen treatment wherein an incoming call originating from a CallScreenDN is terminated without any announcement to the calling party. Although, this embodiment shows an incoming call originating from a DN in the PSTN  125 , a similar signal flow would occur for a call originating from a DN in a WCS. 
     When, for example, a PSTN  125  user dials a WCS subscriber&#39;s DN from a telephone outside the WCS, the LDS receives an ISUP IAM [DN]  2301  message from the PSTN  125  to alert the LDS  104  of an incoming call originating from a particular DN. The LDS  104  determines that the called DN is provisioned for an advanced intelligent network termination attempt (AIN TAT), suspends the delivery of the call, and sends an AIN query, TCAP (AIN Termination_Attempt [DN])  2302  message, to the NSP  106  for an appropriate routing instruction for contacting the called DN. When the NSP  106  receives the AIN TAT it checks the MS  101  user&#39;s service profile feature settings in the WCSD to determine whether the originating telephone number (calling party DN) is a screened telephone number and if so what, if any, Call Screen treatment has been specified by the MS  101  user. In this case, the MS  101  has activated the Call Screen feature/function for the originating DN and programmed the call screen treatment so that the incoming call should be dropped without playing any announcement to the calling party. Therefore, the NSP  106  then determines that the attempted DN is directed to a MS  101 , and that the MS  101  has provisioned the calling party&#39;s telephone number as a CallScreenDN with a call screen treatment of dropping the call without an announcement. 
     In response, the NSP  106  sends a TCAP (AIN Disconnect)  2303  message to the LDS  104 . In response the LDS  104  sends the PSTN  125  an ISUP REL  2304  message to release the PSTN  125  without any announcement. Then the LDS  104  sends the TCAP (AIN Close)  2305  message to close the TCAP transaction. Finally, the LDS  104  sends the PSTN  125  a ISUP RLC  2306  message to indicate a release has been completed. 
     In accordance with a further embodiment of the invention, FIG. 24 illustrates an exemplary call screen call treatment scenario in which an incoming blocked call is sent to a resource, such as an answering service, for example VMS  107 . In this case, the signal flow is similar to the case where the call screen treatment is set to drop the incoming call without providing the calling party an announcement. However, in this case the LDS  104  is instructed to forward the call from the CallScreenDN (calling party number that is provisioned to be screened) to a resource (e.g., VMS  107 ) for a proper announcement directed to the calling party. 
     Once again when, for example, the PSTN  125  user dials the WCS subscriber&#39;s DN, the LDS  104  receives an ISUP IAM [DN]  2301  message from the PSTN  125 . The LDS  104  finds that the DN is provisioned for AIN TAT, suspends the delivery of the call, and sends an AIN query message, TCAP (AIN Termination_Attempt [DN])  2302  to the NSP  106  for an appropriate routing instruction. Then, the NSP  106  checks the WCSD database to determine whether the calling party telephone number (DN) has been designated by the MS  101  user as a screened number and whether the MS  101  user has set a call screen treatment. In this case, the NSP  106  determines that for the called DN (MS  101 ) the incoming calling party&#39;s telephone number is a CallScreenDN and the call treatment requires the call be sent to a resource. So the NSP  106  instruct the LDS  104  that the incoming call is to be sent to a resource, such as the VMS  107  which will allow the calling party to leave a voice message. Thus, the NSP  106  sends a TCAP (AIN SendToResource)  2401  message to the LDS  104 . The LDS  104  sends a TCAP (AIN Close)  2402  message to the NSP  106  to close the TCAP transaction. Finally, the LDS  104  and VMS  107  (Intelligent Peripheral) assume the call processing (Call processing by LDS and VMS  2403 ) enabling the calling party to leave a message for the MS  101  user. 
     In accordance with another preferred embodiment of the invention, FIG. 25 illustrates a call screen treatment scenario in which a screened call is forwarded to a VAP  103  for playing an announcement to the incoming call indicating, for example, that the call has been screened and will be dropped or that the MS  101  user is not interested in the service or product being offered by the calling party. The NSP  106  designates which VAP  103  within the WCS will provide the announcement to the calling party based on, for example, VAP  103  availability. Therefore, the VAP  103  designated to play the announcement is not necessarily the VAP  103  with which the MS  101  is presently resident. 
     When, for example, the PSTN  125  user dials the WCS subscriber&#39;s DN, the LDS  104  receives an ISUP IAM [DN]  2501  message from the PSTN  125 . The LDS  104  recognizes that the called DN is set up for an AIN TAT trigger and sends the NSP  106  an AIN TAT query message, TCAP(AIN Termination_Attempt [DN])  2502 , to get routing information for the incoming call. The NSP  106  checks the WCSD database to determine whether the calling party&#39;s telephone number is a CallScreenDN for the MS  101  being called and whether the MS  101  user has set a particular call screen treatment. Assuming that the NSP  106  determines that the calling party&#39;s DN is designated as a CallScreenDN for the MS  101  being called and the MS  101  user has set a call screen treatment for playing an announcement to the calling party, the NSP  106  sends a Play Announcement Request [Call Screen, FDN]  2503  message to one of the available VAPs, specifies the type of announcement to be played (i.e., Call Screen: Do not call again!) and starts the TPA 1  timer. The message will contain the FDN and the announcement option, Call Screen in this case, along with the MIN, VAP ID, and call reference number (e.g., CR=1). However, if the NSP  106  does not find any VAP  103  to connect to the calling party incoming call or the TPA 1  timer expires before receiving the Play Announcement Result  2519  message from the VAP  103 , it will send a TCAP (AIN Disconnect) message to the LDS  104  and the incoming call will be disconnected without any announcement. 
     Next, the NSP  106  sends a TCAP (AIN Forward_Call [FDN])  2504  message to the LDS  103  directing the LDS  104  to establish a connection between the incoming call from the calling party and the chosen VAP  103  by forwarding the incoming call to the chosen VAP  103 . The LDS  104  then performs a call setup between the selected VAP  103  and the incoming call. First, the LDS  104  sends the VAP  103  a Q.931 Setup [FDN]  2505  message. In response the VAP  103  sends a Q.931 Call Proceeding  2506  message, a Q.931 Alerting  2507  message, and a Q.931 Connect  2509  message to the LDS  104 . In the meantime, the LDS  104  sends an ISUP ACM  2508  message and an ISUP ANM  2510  message to the PSTN  125 . When the incoming call has been properly connected with the selected VAP  103 , the LDS sends a Q.931 Connect ACK  2511  acknowledgement message to the VAP  103  and a TCAP (AIN Close)  2512  message to the NSP  106 . 
     Once the incoming call is connected with the VAP  103 , the VAP  103  plays the announcement (for exarnple, a default announcement, a user defined announcement using voice synthesis, or a user defined announcement that is a recorded message created by the MS  101  user) at step  2513 . The VAP  103  uses, for example, a DSP to provide the announcement or may utilize the VPU  1235  in the NSP  106  to generate the announcement. After the announcement has been played, the VAP  103  initiates a disconnect process with the LDS  104  and the LDS  104  initiates a release process with the PSTN  125 , releasing the VAP  103  and PSTN  125  from the active voice traffic channel. This process is initiated by the VAP  103  sending the LDS  104  a Q.931 Disconnect  2514  message instructing the LDS  104  to disconnect the active call between the VAP  103  and the PSTN  125 . The LDS  104  releases the active call connection with the VAP  103  by sending a Q.931 Release  2517  message and releases the active call connection with the PSTN  125  by sending a ISUP REL  2516  message. The PSTN  125  notifies the LDS  104  that the call has been disconnected by sending an ISUP RLC Complete  2518  message to the LDS  104 . The VAP  103  notifies the LDS  104  that the call has been disconnected by sending a Q.931 Release Complete  2517  message to the LDS  104 . Finally, the VAP  103  sends a Play Announcement Result [Success]  2519  message to the NSP  106 , indicating that the announcement was played successfully for the incoming call, and cancels timer TPA 1 . The Play Announcement Result message includes a VAP ID, FDN, Call Reference Number, Result, and Cause fields. As previously indicated, if the TPA 1  timer expires before receiving Play Announcement Result  2519  message is received from the VAP  103 , it will send a TCAP (AIN Disconnect) message to the LDS  104  if not sent already, and the call will be disconnected without any announcement. 
     XV. Call Forwarding 
     A. Unconditional Call Forwarding 
     A user of the MS  101  may not always have the MS  101  with him or her. It may be useful in such a situation to allow for incoming calls to the MS  101  to be forwarded to another predetermined DN or DNs. This DN to which calls are forwarded is referred to herein as the FwdDN. Various types of call forwarding are available in the WCS  140 . For example, calls may be forwarded unconditionally, such that a call to a DN that would otherwise be destined for the MS  101  associated with the DN would be forwarded instead to a predetermined FwdDN. This unconditional call forwarding feature may alert both the MS  101  and the communication device at the FwdDN, or only the communication device at the FwdDN such that the MS  101  is not alerted at all. 
     To activate this “unconditional call forwarding” feature, the MS  101  user may dial a feature activation code such as *90#[FwdDN], followed by the SEND button on the MS  101 . In this example, “*90” indicates the unconditional call forwarding feature. The phrase FwdDN in the brackets “[ ]” represents the intended DN to which a call should be forwarded (the brackets themselves are not actually dialed in this example). To deactivate the unconditional call forwarding feature, the MS  101  user may enter a sequence such as *900 (or other appropriate sequence) followed by the send button. 
     FIG. 26 is an exemplary flow chart of how the unconditional call forwarding feature may work. A call may be made directed to the MS  101  subscriber&#39;s DN (step  2601 ). A determination is made whether the unconditional call forwarding feature has been activated for the MS  101  (step  2602 ). If so, then FwdDN is determined (step  2603 ) and the call is automatically forwarded to FwdDN (step  2604 ). If the unconditional call forwarding feature has not been activated for the MS  101 , then the call is routed to the MS  101  and/or further processing is performed on the call. 
     An exemplary embodiment of how the above steps for unconditional call forwarding may be performed is now described with reference to FIG.  27 . Once the unconditional call forwarding feature has been activated for an MS  101 , a PSTN  125  or WCS  140  user may dial the called WCS  140  subscriber&#39;s DN. Responsive to the LDS  104  receiving the incoming call for the WCS  140  subscriber at DN (the call is assumed in this example to be initiated from the PSTN  125 ) (step  2701 ), a TCAP AIN TAT message may be sent from the LDS  104  to the NSP  106  (step  2703 ). Upon receipt of the TCAP AIN TAT message, the NSP  106  may check the feature activation table for the MS  101  and may determine that the MS  101  has activated the unconditional call forwarding feature. The NSP  106  may further check the subscriber profile and find that the unconditional call forwarding feature is active for the called MS  101 . If the unconditional call forwarding feature is active, the NSP  106  may retrieve the call forwarding number (FwdDN). The NSP  106  may immediately use the FwdDN as the forwarding number and may send a TCAP (AIN Forward_Call) message to the LDS  104  (step  2705 ). The LDS  104  may then assume the call processing and forward the call to FwdDN (step  2707 ). 
     B. Programmable Ring Call Forwarding 
     Call forwarding may alternatively or additionally be configured to forward a call in response to a selected number of rings occurring at the called MS  101  and/or the passage of a certain amount of time. For example, a call may be forwarded to FwdDN after three seconds have passed (e.g., after three seconds of alerting time at the MS  101 ). As another example, the call may be forwarded after eight seconds have passed. 
     To activate this “programmable ring call forwarding” feature, the MS  101  user may dial a feature activation code such as *91*4#[FwdDN], followed by the SEND button on the MS  101 . Such a command may indicate that calls should be forwarded to FwdDN after four seconds. In this example, “*91” indicates the programmable ring call forwarding feature, and the “4” after the star sign indicates either the number of seconds or the number of rings after which a call should be forwarded, depending upon how the WCS  140  is configured. This number may be in the range of, e.g., 0 to 30 seconds, or 0 to 10 rings, changeable through the WCS  140  OA&amp;M interface. To deactivate the programmable ring call forwarding feature, the MS  101  user may enter a sequence such as *910 followed by the send button. If no amount of time is specified by the user (e.g., by dialing *91#[FwdDN]) or the amount of time entered is out of range, then a default amount of time, such as four seconds, may be used. 
     FIG. 32 is an exemplary flow chart of how the programmable ring call forwarding feature may work. Referring to the same call as in FIGS. 26,  28 , and  30 , and if the call has not yet been forwarded to FwdDN, a determination is made whether the programmable ring call forwarding feature has been activated for the MS  101  (step  3201 ). If this feature has not been activated, then the MS  101  is alerted to the call (e.g. by ringing the MS  101 ) and the call routed to the MS  101  upon answering (step  3202 ) and/or further processing is performed on the call. If the programmable ring call forwarding feature has been activated for the MS  101 , then a time-out period is determined (step  3203 ). The time-out period may either be predetermined by the subscriber or set to a default value. The MS  101  is also alerted to the existence of the call, and a timer for timing the time-out period is started (step  3204 ). It is determined whether the call has been answered at the MS  101  before the timer has finished (step  3205 ), and if so, then the call is routed to the MS (step  3206 ). If the call has not been answered within the allotted time, then FwdDN is determined ( 3207 ) and the call is forwarded to FwdDN (step  3208 ). 
     An exemplary embodiment of how the above steps for programmable ring call forwarding may be performed is now described with reference to FIG.  33 . Once the programmable ring call forwarding feature has been activated for the MS  101 , an incoming call to the subscriber&#39;s DN is automatically forwarded to the FwdDN after the selected amount of time or number of rings. A PSTN  125  or WCS  140  user may dial the WCS  140  subscriber&#39;s DN (i.e., the subscriber who has activated the programmable ring call forwarding feature). The LDS  104  may receive the ISUP IAM message associated with the call (the call is assumed in this example to be initiated from the PSTN  125 ) (step  3301 ). In the present embodiment, the LDS  104  may determine that the dialed DN is provisioned for AIN Termination Attempt Trigger (TAT). Responsive to such a determination, the LDS  104  may suspend delivery of the call and may send an AIN query message to the NSP  106  (step  3303 ) for an appropriate routing instruction. 
     When the NSP  106  receives the AIN TAT message, the NSP  106  may find that the subscriber&#39;s MS  101  is active and idle in its serving area. The NSP  106  may then page the MS  101  through the VAP  103  (steps  3305 ,  3307 ) using IS-136 paging procedures, and may also start a TT 6  timer  3308 . As part of the page request message in step  3305 , the NSP  106  may send the MSID that the VAP  103  will use to complete the incoming call setup procedure. When the MS  101  responds to the page (steps  3309 ,  3311 ), the VAP  103  may forward the page response in the form of a Page Response message, which includes the Forward Directory Number (FDN), to the NSP  106  (step  3313 ). The VAP  103  may also start an event timer TT 5   3314  at this time to prevent permanent holding of RF and ISDN B-channel resources. 
     If the TT 6  timer  3308  expires and the NSP  106  has not received the Page Response message in step  3313 , the NSP  106  may authorize call termination to the DN. On the other hand, if the NSP  106  receives the Page Response message before the TT 6  timer  3308  expires, the NSP  106  may cancel the TT 6  timer  3308  and determine that the current VAP  103  has the resources to serve the incoming call. The NSP  106  may also check whether the programmable ring call forwarding feature is active for the particular MS  101 . The NSP  106  gets the TFPR value, which signifies the time period for which the MS  101  should ring before the call should be forwarded, from the subscriber profile. At this point, the NSP  106  may direct (using a TCAP Conversation package) the LDS  104  to forward the call to the FDN of the VAP  103  serving the MS  101  (step  3315 ). The TCAP Conversation package may include the T(NoAnswer) timer value in the TCAP AIN message to indicate the length of the ringing after which the call shall be forwarded. The message may be in the form of TCAP (AIN Forward_Call[FDN], NEL[O_No_Answer], T(NoAnswer)), where T(NoAnswer) is set to be the time after which the call should be forwarded. For example, where the user activated the programmable ring call forwarding feature as *91*5#[FwdDN], then T(NoAnswer) would be set to five seconds. 
     The LDS  104  may start the T(NoAnswer) timer  3318  for the FDN and send a Q.931 Setup message to the VAP  103  (step  3317 ). Upon receipt of the Q.931 Setup message, the VAP  103  may cancel the TT 5  timer  3314 , initiate DTC designation to the MS  101  (step  3319 ), start a TT 2  timer  3320 , and send a Q.931 Call Proceeding message to the LDS  104  (step  3321 ). 
     At this point, the MS  101  may tune to the traffic channel. When the VAP  103  detects that the MS  101  is on the traffic channel via a DVCC status change (step  3323 ), the MS  101  may cut through the ISDN/B-Channel and initiate the Alerting procedures to both the call legs (i.e., in both the LDS  104  and MS  101  directions). The VAP  103  may send an IS-136 Alert-With-Info message to the MS  101  (step  3325 ) and wait for an IS-136 Mobile ACK message from the MS  101  (step  3351 ). When the VAP  103  receives the Mobile ACK message, the VAP  103  may start a TT 4  timer  3326  and send a Q.931 Alerting message to the LDS  104  (step  3327 ). Upon receipt of the Q.931 Alerting message, the LDS  104  may send an ISUP ACM message to the switch in the PSTN  125  (step  3329 ) and generate a ring-back tone towards the calling party (step  3331 ). 
     When the T(NoAnswer) timer  3318  expires on the LDS  104 , the LDS  104  may send an event notification to the NSP  106  (step  3333 ) in the form of an AIN O_No_Answer trigger. Upon receipt of the AIN O_No_Answer trigger, the NSP  106  may check if the programmable ring call forwarding feature is active for the MS  101 . If the feature is active, the NSP  106  may get the call forwarding number from the subscriber profile and direct the LDS  104  to forward the call to the call forwarding number (FwdDN) (step  3335 ) using a TCAP (AIN Forward_Call[FwdDN]) message. The LDS  104  may then release the ISDN-B channel setup by sending a Q.931 Disconnect message to the VAP  103  (step  3337 ). 
     In response to the Q.931 Disconnect Message, the VAP  103  may send a Q.931 Release message to the LDS  104  (step  3339 ). In response, the LDS  104  may send a Q.931 Release Complete message to the VAP  103  (step  3341 ). The VAP  103  may release the RF resources by sending an IS-136 Release message to the MS  101  (step  3343 ), and may send a Termination Result [fail] message to the NSP  106  (step  3345 ). The MS  101  may send an IS-136 Mobile ACK message to the VAP  103  (step  3347 ). At this point, call processing may be assumed by the LDS  104  and the call will be forwarded to FwdDN (step  3349 ). 
     If the call is answered at the MS  101  before the T(NoAnswer) timer  3318  expires, or if the programmable ring call forwarding feature is not activated for the MS  101 , then the call will be processed normally without the call being forwarded (unless another call forwarding feature as described herein is activated for the MS  101 ). 
     C. Busy Call Forwarding 
     Call forwarding may alternatively or additionally be configured to forward a call depending upon whether the subscriber&#39;s MS  101  is busy (i.e., currently handling a call). For example, incoming calls to the subscriber&#39;s DN may be routed to the subscriber&#39;s MS  101  when it is not busy, and forwarded to FwdDN when the MS  101  is busy. 
     To activate this “busy call forwarding” feature, the MS  101  user may dial a feature activation code such as *93#[FwdDN], followed by the SEND button on the MS  101 . In this example, “*93” indicates the busy call forwarding feature. To deactivate the busy call forwarding feature, the MS  101  user may dial, e.g., *930 and then the SEND button. 
     FIG. 28 is an exemplary flow chart of how the busy call forwarding feature may work. Referring to the same call as in FIG. 26, and if the call has not yet been forwarded to FwdDN, a determination is made whether the busy call forwarding feature has been activated for the MS  101  (step  2801 ). If so, it is then determined whether the MS  101  is busy (step  2802 ). If the busy call forwarding feature is active and the MS  101  is busy, then FwdDN is determined (step  2803 ) and the call is automatically forwarded to FwdDN (step  2804 ). If the busy call forwarding feature has not been activated for the MS  101  and/or the MS is not busy, then the call is routed to the MS  101  and/or further processing is performed on the call. 
     An exemplary embodiment of how the above steps for busy call forwarding may be performed is now described with reference to FIG.  29 . Once the busy call forwarding feature has been activated for the MS  101 , an incoming call will be automatically forwarded to FwdDN if the MS  101  is busy. When the LDS  104  receives an incoming call for the WCS  140  user (DN) (step  2901 ), the LDS  104  may send a TCAP AIN TAT message to the NSP  106  (step  2903 ). Upon receipt of the TCAP AIN TAT message, the NSP  106  may check the feature activation table for the MS  101  and determine whether the MS  101  has activated the busy call forwarding feature. The NSP  106  may also determine whether the MS  101  is currently busy. If the MS  101  is currently busy (e.g., busy due to call  2901 ) and the busy call forwarding feature is activated for the MS  101 , the NSP  106  may use the FwdDN as the forwarding number and send a TCAP (AIN Forward_Call) message to the LDS  104  (step  2905 ). The LDS  104  may then assume call processing and forward the call to FwdDN (step  2907 ). If the MS  101  is not currently busy, or if the busy call forwarding feature is not activated for the MS  101 , then the call will be processed normally without being forwarded (unless another call forwarding feature as described herein is activated for the MS  101 ). 
     D. Time-of-Day Call Forwarding 
     Call forwarding may alternatively or additionally be configured to forward a call depending upon the time of day, day of week, and/or date. For example, a call may be forwarded to FwdDN on weekends but not on weekdays. As another example, incoming calls to a particular subscriber&#39;s DN may be forwarded to a first FwdDN between begin time 9:00 a.m. and end time 6:00 p.m., to a second different FwdDN between begin time 6:00 p.m. and end time 8:00 p.m., and not forwarded at all other times (i.e., routed to subscriber&#39;s normal MS  101  at all other times). 
     To activate this “time-of-day call forwarding” feature, the MS  101  user may dial a feature activation code such as *92*[BeginTime]*[EndTime]#[FwdDN], followed by the SEND button on the MS  101 . In this example, “*92” indicates the time of day call forwarding feature. “[BeginTime]” indicates the selected begin time, and “[EndTime]” indicates the selected end time. The begin and end times may be entered in any format. For example, the format may be a 24-hour military time format, such that if the chosen begin time is 8:30 a.m., and the chosen end time is 6:00 p.m., then BeginTime would be entered by the subscriber as 0830 and EndTime would be entered as 1800. To deactivate the time-of-day call forwarding feature, the MS  101  user may dial, e.g., *920 and then the SEND button. 
     FIG. 30 is an exemplary flow chart of how the time-of-day call forwarding feature may work. Referring to the same call as in FIGS. 26 and 28, and if the call has not yet been forwarded to FwdDN, a determination is made whether the time-of-day call forwarding feature has been activated for the MS  101  (step  3001 ). If so, it is then determined whether the current time is between predetermined begin and end times (step  3002 ). If the time-of-day call forwarding feature is active and the current time is between the begin and end times, then FwdDN is determined (step  3003 ) and the call is automatically forwarded to FwdDN (step  3004 ). If the time-of-day call forwarding feature has not been activated for the MS  101  and/or the current time is not between the begin and end times, then the call is routed to the MS  101  and/or further processing is performed on the call. 
     An exemplary embodiment of how the above steps for time-of-day call forwarding may be performed is now described with reference to FIG.  31 . Once the time-of-day call forwarding feature has been activated for the MS  101 , an incoming call to the subscriber&#39;s DN is automatically forwarded to FwdDN depending upon the time, data and/or day. When the LDS  104  receives an incoming call for the WCS  140  user (DN) (step  3101 ), the LDS  104  may send a TCAP AIN TAT message to the NSP  106  (step  3103 ). Upon receipt of the TCAP AIN TAT message, the NSP  106  may check the feature activation table for the MS  101  and determine that the MS  101  has activated the time-of-day call forwarding feature. The NSP  106  may check a clock (such as the internal clock of the NSP  106 ) and compare the clock with the user-programmed time period(s). For example, the NSP  106  may check whether the current time as indicated by the clock is between the begin time and the end time of each user-programmed time period. 
     If the clock is within one of the user-programmed time periods, the NSP  106  may use FwdDN as the forwarding number and send a TCAP (AIN Forward_Call) message to the LDS  104  (step  3105 ). The LDS  104  may then assume call processing and the call is forwarded to FwdDN (step  3107 ). If the current time as indicated by the clock is not within one of the user-programmed time periods, or if the time-of-day feature is not activated for the MS  101 , then the NSP  106  may treat the incoming call as a normal incoming call, such that the incoming call will not be forwarded (unless another call forwarding feature as described herein is activated for the MS  101 ). 
     Any or all of the above-described features may be activated, deactivated, and/or otherwise configured in any combination or subcombination desired for a particular MS  101 . For example, call forwarding for a particular MS  101  may be configured so as to unconditionally forward calls on weekends, and to forward calls only after six seconds on weekdays. Such activation, deactivation, and/or other configuration of the features may be controlled by the user via the MS  101 , via a telephone call to the service provider (e.g., a customer service representative), via the Internet, and/or via an intranet or other private or public network coupled to the WCS  140 . Alternatively, the WCS  140  may be configured such that only one call forwarding feature at a time may be activated for a particular MS  101 . In such an embodiment, if a call forwarding feature is activated while an existing call forwarding feature is already activated for the MS  101 , the new call forwarding feature may replace the existing call forwarding feature. 
     FIG. 34 illustrates a display of an exemplary interactive Internet web page  3400  for activating, deactivating, and/or configuring features described herein. The web page  3400  may allow a user to define one or more FwdDNs to which calls should be forwarded depending upon one or more conditions. An advantage to using an Internet web page to. activate, deactivate, and/or configure features is that the user may see the entire configuration on one display. This may be important if the user has selected a particularly complex feature configuration. When the Internet is used to configure call forwarding features or other features, a server that runs the web page  3400  may be coupled to the WCS  140 . 
     The web page  3400  shown in FIG. 34 includes one or more forwarded number text boxes  3401  within which a user can enter selected FwdDNs, check boxes  3402  for selecting whether a call should be unconditionally forwarded to a particular FwdDN, text boxes  3403  for selecting how many rings should occur at the MS  101  (and/or how much time to wait) before forwarding a call for a particular FwdDN, check boxes  3404  for selecting whether a call should be forwarded to a particular FwdDN when the MS  101  is busy, and text boxes  3405  for selecting time ranges within which a call should be forwarded to a particular FwdDN. Of course, the web page  3400  may include any type of text box, check box, pull-down menu, scroll box, etc., any of which may be used interchangeably as desired with any of the text boxes and/or check boxes  3401 - 3405 . What is important is that the web page  3400  allows the user to configure the call forwarding features and/or other calling features for his/her MS  101 . 
     For example, as shown in FIG. 34, call forwarding for an MS  101  having a DN 123-123-4567 may be configured on the web page  3400  to unconditionally forward all incoming calls, but only on weekends, to FwdDN 123-456-7890. Call forwarding for the same MS  101  may further be configured to forward incoming calls after three rings at the MS  101 , but only on Mondays between 8:00 a.m. and 6:00 p.m., to FwdDN 234-567-8901. Call forwarding for the same MS  101  may further be configured to forward incoming calls after two rings at the MS  101  or when the MS  101  is busy, but only on Oct. 26, 1999, to FwdDN 345-678-9012. Thus, a particular MS  101  may have multiple call forwarding and/or other features simultaneously configured. If there is a conflict in features (e.g., unconditional call forwarding at all times in combination with call forwarding only when busy at all times), then the web page  3400  may indicate to the user that such a conflict exists and that the features should be re-configured accordingly. 
     XVI. Call Waiting 
     FIG. 35 provides an exemplary call flow diagram for implementing the call waiting feature according to an illustrative embodiment of the present invention. 
     For purposes of this discussion, it will be assumed that there exists an active call  3502  between a mobile station MS  101 A and a party coupled to the PSTN  125 . The call  3502  in progress is referred to by the VAP  103 A and the NSP  106  as having a call reference value, CR=1, and a B Channel ID (Ch ID=B 1 ). When a second call originating from within the PSTN  125  is made to a DN of a party in a WCS system, such as a party using MS  101 A, an ISUP IAM [DN] message  3504  is received by the LDS  104 . The LDS  104  processes the ISUP IAM message  3504  and discovers that the called party&#39;s DN is provisioned for AN call treatment. Then, the LDS  104  sends an AIN query message, TCAP (AIN Termination Attempt [DN]) message  3506 , to the NSP  106  for an appropriate routing instruction. Responsive to the AIN query message and knowing that the MS  101 A is involved in an active call  3502 , the NSP  106  determines if the MS  101 A subscribes to the call waiting feature by checking the WCSD (Wireless Centrex System Database) and determines if the call waiting feature is currently available and has been activated by the subscriber. 
     If the MS  101 A does not subscribe to the call waiting feature or the feature is not presently available such as by being deactivated, the NSP  106  sends a TCAP message (not shown) to the LDS  104  with Authorize Term (authorize termination) message to the original DN. The call waiting feature may not be available due to manual or automatic deactivation. According to one embodiment of the invention, the user may manually deactivate the call waiting feature when they do not want to be interrupted by, for example, pressing a special key code on their handset prior to making a call. Also, the call waiting feature may be automatically deactivated in a number of instances, such as: 1) when the MS is already engaged in a conference call; 2) when the MS is already engaged in another call waiting; 3) when the MS has received an automatic callback call with another call on hold; and 4) as predetermined by the subscriber including based on the physical location of the MS, the time of day, or the other party on the original call. When the LDS  104  receives the Authorize Term message, the incoming call may be connected to the DN (desktop phone) or coupled to the VMS  107  for further handling. 
     If the MS  101 A subscribes to the call waiting feature and it is presently available or active, then the NSP  106  sends an AIN Forward Call message in a TCAP conversation package  3508  to the LDS  104 . The TCAP conversation package  3508  directs the LDS  104  to forward the call to the FDN (forward directory number). The FDN is the DN in the VAP  103 A that is used to deliver the call to the MS  101 A. The LDS  104  then sends a Q.931 Setup message  3510  including the FDN, a call reference value (CR=2) and a second B Channel ID (Ch ID=B 2 ) to the VAP  103 A and starts a No Answer Timer (T(NoAnswer)). The VAP  103 A responds to the Q.931 Setup message  3510  by sending a Q.931 Call Proceeding message  3512 . 
     Next, the VAP  103 A sends the NSP  106  a Call Waiting Proceeding message  3520  including the MSID and FDN and starts the TCW 1  timer (first call waiting timer). In response, the NSP  106  sends a Play Voice Prompt message  3522  including a call waiting tone to the VAP  103 A and starts the TCW 2  timer (second call waiting timer). Upon receipt of the Play Voice Prompt message  3522 , the VAP  103 A cancels the TCW 1  timer and generates and plays the call waiting (CW) tone  3524  to the user of MS  101 A. The tone may be generated and played at a preset interval for a preset duration, such as every five seconds for one minute. 
     While the CW tone  3524  is being generated, the VAP  103 A sends a Q.931 alerting message  3514  to the LDS  104 . The LDS  104  responsive to the Q.931 alerting message  3514  sends an ISUP ACM message  3516  to the switch in PSTN  125 . In the meantime, the LDS  104  sends a ring back tone  3518  to the PSTN  125  caller. 
     The user of MS  101 A may choose to answer the incoming call by sending a message to the VAP  103 A before T(NoAnswer) expires. According to an illustrative embodiment of the invention, the user can answer the incoming call and place the existing call on hold by pressing the “send” button, which in turn sends an IS-136 Flash with Info message  3526  to the VAP  103 A. In response, the VAP  103 A sends a Feature Request [Flash with Info] message  3528  to the NSP  106  and starts the TCW 3  (third call waiting timer). Also, the VAP  103 A sends an IS-136 Flash with Info ACK message  3530  to the MS  101 A acknowledging receipt of the Flash with Info message  3526 . When the NSP  106  receives the Feature Request [Flash with Info] message  3528 , it cancels the TCW 2  timer and sends a Feature Request ACK [Hold and Answer Call Waiting] message  3532  to the VAP  103 A and starts the TCW 4  timer (fourth call waiting timer). Next, the VAP  103 A cancels the TCW 3  timer and initiates the Q.932 call hold procedure for the existing call (CR=1) by sending a Q.932 Hold [CR=1] message  3534  to the LDS  104 . The LDS then responds by sending a Q.932 Hold ACK [CR=1] message  3536  to the VAP  103 A to acknowledge that the current call is held, Call Held (CR=1)  3538 . 
     The VAP  103 A sends a Q.931 Connect [CR=2] message  3540  to LDS  104  to cause initiate connection of the incoming call (CR=2). The LDS  104  then cancels the T(NoAnswer) timer and sends an ISUP ANM message  3542  to PSTN  125  switch to cut through the voice path  3548 . After the LDS  104  sends an ISDN Q.931 Connect ACK message  3544  to the VAP  103 A for the incoming call, it sends a TCAP (AIN Close) message  3550  to the NSP  106 . Meanwhile, the VAP  103 A sends a Hold &amp; Answer Call Waiting Result [success] message  3546  to the NSP  106  indicating that the call waiting process has been successful. Then, the NSP  106  cancels the TCW 4  timer and the voice path  3548  is established for the incoming call while the original call (CR=1)is placed on hold. The voice path  3548  has a call reference value of CR=2 and a B Channel ID, Ch ID=B 2 . 
     It should be understood that the MS user could proactively handle the second call as described in other portions of this application in conjunction with the call waiting feature. Also, the user may switch back and forth between the second call (CR=2) and the original call (CR=1) in a number of ways. For example, the user may press the “send” button and reinitiate the process described in FIG. 35 beginning with sending IS-136 Flash with Info message  3526  as set forth above. 
     FIG. 36 provides an illustrative flow diagram for implementation of the call waiting feature according another embodiment to the present invention in which much of the intelligence is distributed to the VAP  103 A rather than in the NSP  106 . 
     In step S 361 , an existing call (CR=1) between a PSTN user and MS  101 A is in progress and a new call arrives for the MS  101 A. Next, in step S 362 , the NSP  106  determines whether the call waiting feature is available for the MS  101 A. If the NSP  106  determines that call waiting is not available, then the NSP  106  informs the LDS  104  that the MS  101 A is busy in step S 363  and a busy signal can be returned to the PSTN user, or another call routing procedure may be implemented such as routing the call for further handling as described elsewhere in the application, such as to the desktop phone associated with the MS  101 A or the VMS  107 . Alternatively, if the NSP  106  validates that call waiting is available, then, in step S 364 , the NSP  106  instructs the VAP  103 A to initiate the call waiting procedure and the LDS  104  to forward the call to the VAP  103 A. 
     In step S 365 , it is determined whether the call (CR=2) has been established successfully to the VAP  103 A and the MS  101 A. If the call has not been established successfully in step S 365 , then, in step S 366 , the VAP  103 A cancels the call waiting procedure and informs the NSP  106  of the cancellation, which causes the NSP  106  to initiate the call release procedure. If the call has been established successfully, the LDS generates a ringback tone to the calling party and the VAP  103 A sends a call waiting signal to the MS  101 A and waits for a response thereto in step S 367 . 
     The VAP  103 A waits a predetermined period of time for a response from the MS  101 A user in step S 368 . If the VAP  103 A timer expires in step S 368 , the VAP  103 A informs the NSP  106  to release the call (CR=2) in step S 369  similarly to step S 366 . However, if the MS  101 A responds within the time period, the VAP  103 A initiates the call hold procedure in which the LDS  104  places the original call (CR=1) on hold and the incoming call (CR=2) is established between the PSTN user and the MS  101 A in step S 370 . Also, in step S 360 , the VAP  103 A informs the NSP  106  of the successful call waiting result. In step S 371 , the MS  101 A user may toggle back and forth between the new call (CR=2) and the original call (CR=1) putting one on hold while communicating in the other. 
     XVII. Distinctive Ringing 
     The distinctive ringing feature allows a subscriber to be alerted by a distinctive indication, e.g., a ring, of an incoming call originated from a communications unit assigned a specific directory number (DN). A subscriber can provision one or more DNs that cause a distinctive ring to occur when a communications unit assigned a provisioned DN initiates a call to the subscriber. 
     There are several ways a subscriber can provision the distinctive ringing DN list. For example, the user may access the Internet or a web-based interface such as a WCS web site and input and update the DN list. Also, the subscriber may contact a customer care center representative by phone and verbally communicate the numbers through any type of communications unit (e.g., cell phone, landline phone, wireless palm top computer phone, etc.). Alternatively, a user may be directed through an automated phone menu to input the numbers by use of a communications unit keypad or voice recognition system. 
     According to one embodiment, the user may provision the distinctive ringing services through the WCS system. In this regard, the subscriber may activate the feature by entering a feature activation code followed by a DN (e.g., *70#5555151) into the keypad of MS  101 A and then pressing the “send” button. Actuation of the “send” button sends the feature activation message to the WCS system (e.g., NSP  106 ). The WCS system then may acknowledge activation of the feature and phone number by, for example, returning a short message to the MS  101 A. In addition, a message indicating that a call origination request has been rejected may contain feature activation/deactivation status information to be displayed to the user. 
     In a further modification, a subscriber can select a specific distinctive ring for each DN from a plurality of available rings (e.g., 5 ring tones). For example, a subscriber may identify personal calls by one distinctive ring type (e.g., ring type  1 ), business calls by another distinctive ring type (ring type  2 ), and a very important call by yet another ring type (ring type  3 ). Also, the subscriber may define a distinctive ring for all calls originating from parties who have blocked their number pursuant to call blocking. Thus, the subscriber might send the feature activation code followed by the ring type and the DN (e.g., *70#2#5555151) to the WCS system. When the subscriber fails to enter a ring type, a default distinctive ring (e.g., ring type  1 ) can be assigned to the DN. 
     To remove a phone number from the DN list, the subscriber, in addition to the methods note above, may enter a feature deactivation code followed by the DN (e.g., *700#DN) and press the “send” button. Also, the subscriber may deactivate the distinctive ringing for all numbers by entering a feature deactivation code (e.g., *700#*) and the “send” button on the MS  101 A. A more detailed discussion of feature activation and deactivation is provided at other places in the instant description, for example at section IX. 
     According to an illustrative embodiment of the invention, the DN list may be stored in a memory in the NSP  106  or a memory location accessible to the NSP  106 . The DN list may include any amount of numbers depending on the capacity of the memory employed. In one embodiment, up to thirty numbers may be preset for distinctive ringing. In this embodiment, if a subscriber attempts to provision a thirty-first number, the system may reject the provision or alternatively overwrite the first number provisioned (a first-in-first-out (FIFO) scheme). Also, the size of the phone number in the list can be set according to the capacity of the memory. In an illustrative embodiment, the size of the numbers in the list may range from four to fifteen digits. Also, it should be understood that a DN of a calling party outside or inside the WCS environment may be defined to have a distinctive ring. 
     FIG. 37 provides an exemplary call flow diagram for implementing the distinctive ringing feature according to an illustrative embodiment of the present invention. While the IS-136 standard is used to illustrate one implementation of the present invention, it should be understood that the present invention is applicable to other cellular or PCS systems. 
     When a user of the PSTN  125  dials the DN of a WCS subscriber, the LDS  104  receives an ISUP IAM message  3702  from the PSTN  125 . If the dialed DN is provisioned for AIN Termination Attempt Trigger (TAT), the LDS  104  suspends the delivery of the call and sends an AIN query message  3704  (i.e., TCAP (AIN Termination_Attempt [DN])) to the NSP  106  for an appropriate routing instruction. 
     The NSP  106  upon receipt of the AIN query message  3704  determines if the DN of the calling party is a number for which distinctive ringing is desired (i.e., a DR_DN). For example, the NSP compares the DN of the calling party with each DR_DN in the distinctive ringing list for the MS  101 A (e.g., in the wireless centrex system database (WCSD) entry for the MIN of MS  101 A). If the DN of the calling party matches a DR_DN in the distinctive ringing list, the NSP  106  retrieves the information regarding the distinctive ring from its storage location and specifies in the “signal” portion of a page request message  3706  that a distinctive ring should be provided for the MS  101 A. Also, if multiple distinctive ring tones are available, the NSP  106  indicates the specific distinctive ring tone for reception by the MS  101 A in the “signal” portion of the page request message  3706 . Assuming the subscriber&#39;s MS  101 A is active in the service area of the NSP  106 , the NSP  106  sends the page request message  3706  (i.e., Page Request [MSID, signal]) to the VAP  103 A serving MS  101 A. 
     When the NSP sends the page request message  3706  to the VAP  103 A, a timer TDRI starts. Responsive to the page request message  3706 , the VAP  103 A sends an IS-136 Page message  3708  to the MS  101 A. If the MS  101 A does not respond to the IS-136 page message  3708  before timer TDRI expires, then the call is terminated in another manner by transfer to the VMS, user&#39;s desktop phone or otherwise as described herein. Otherwise, the MS  101 A responds to the IS-136 page message  3708  via an IS-136 page response message  3710  sent to the VAP  103 A. In turn, the VAP  103 A sends a page response message  3712  (i.e., Page Response [FDN] to the NSP  106 . 
     After receiving the page response message  3712 , the NSP  106  directs LDS  104  to forward the call to the Forward Directory Number (FDN) of the VAP  103 A serving the MS  101 A in a TCAP conversation package  3714 , TCAP (AIN Forward_Call [FDN], NEL [O_No_Answer]). The NSP  106  also indicates its interest in event (O_No_Answer for FDN) by sending next event list NEL [O_No_Answer]) information to the LDS  104  in a request component that accompanies the routing component in the TCAP conversation package  3714 . The LDS  104  then starts a No Answer Timer TT 10  for the FDN. Also, LDS  104  sends a Q.931 setup [FDN] message  3716  to the VAP  103 A. 
     The VAP  103 A then sends an IS-136 digital traffic channel (DTC) designation message  3718  to the MS  101 A. Also, VAP  103 A sends a Q.931 call proceeding message  3720  to the LDS  104 . The MS  101 A then tunes to the digital traffic channel and responds to the VAP  103 A with MS on DTC message  3722 . The VAP  103 A detects the MS  101 A on the appropriate traffic channel. Next, the VAP  103 A alerts MS l 10 A with an alert-with-info [signal] message  3724 . The alert-with-info message  3724  includes the appropriate distinctive ringing tone, if any, for play to the subscriber of the MS  101 A. The VAP  103 A then sends a Q.931 alerting message  3726  to LDS  104 . The MS  101 A acknowledges receipt of the alert-with-info message  3724  by sending the VAP  103 A an IS-136 mobile acknowledge (Mobile ACK) message  3728 . Upon receiving the Q.931 alerting message  3726 , the LDS  104  sends an ISUP ACM message  3730  to the switch in PSTN  125 . Meanwhile, the LDS  104  sends a ririgback tone  3732  to the calling party from the PSTN  125 . 
     When the MS  101 A answers (before TT 10  expires), it sends an IS-136 connect message  3734  to the VAP  103 A. The VAP  103 A then sends Q.931 connect message  3736  to the LDS  104  in response to the IS-136 connect message  3734  from MS  101 A. The LDS  104  then cancels timer TT 10  and sends ISUP ANM message  3738  to the PSTN  125  switch and cuts through the voice path  3746 . After the LDS  104  sends a Q.931 connect ACK message  3740  to the VAP  103 A, it then sends TCAP (Completed) message  3742  to the NSP  106  to complete the TCAP transaction. Responsive to Q.931 connect ACK message  3740 , the VAP  103 A sends termination result [Success] message  3744  to the NSP  106  for billing and other OAM&amp;P purposes. At this point, voice path  3746  has been established and the call proceeds between the calling party from the PSTN  125  and the MS  101 A subscriber. 
     XVIII. Returning Calls 
     Technologies that facilitate wireless communication are emerging at an ever-faster rate. Such technologies are employed in end-user devices such as pagers, communication systems, and mail systems such as voice mail and email systems. In wireless communication systems, a need exists to provide a new service in the wireless environment that is analogous to the call return feature provided on wired telephone handsets. A user may be unable to answer his wireless handset when a call is received. For example, the user may be in a meeting where the call would be perceived as a disruption, may be waiting for another call, may be busy on another call, or may not wish to interrupt whatever he is doing when he receives the incoming call. 
     In existing wireless handsets, a user may preset his wireless phone to avoid disruption of his activity when the incoming call arrives, but no provision has been made to allow the user to automatically return the call at a later, more convenient time. Thus, a user who is interrupted or busy cannot avoid answering the incoming call without one of: either missing the call entirely or having to manually redial a number saved on the terminal or on a system that indicates the phone number of the caller. Clearly, there is a need for a system, wireless apparatus and method for allowing a user the flexibility of automatically dialing back an incoming call in a wireless communication system. 
     The present invention provides a system, wireless apparatus and method for allowing a user the flexibility of automatically dialing back an incoming call in a wireless communication system at a time convenient to the user that received the call, a functionality that is analogous to the call return feature provided on wired telephone handsets. For example, a wireless phone may implement the present invention. 
     In the example below, implementation of the present invention is accomplished using a wireless phone in a Wireless Centrex System  140  (WCS). The WCS  140  provides a private wireless access system that is unconnected to any public macro-cellular system and provides Centrex-type services. FIG. 11B shows a block diagram of an illustrative architecture of a WCS platform wherein the present invention may be utilized. The WCS platform includes a local digital switch  104  (LDS), a remote digital terminal  102  (RDT, e.g., SLC-2000), a network server platform  106  (NSP), voice access ports  103 A,  103 B (VAP) and a plurality of associated IS-136 digital time division multiple access (TDMA) cellular or personal communications service (PCS) mobile stations  101 A,  101 B which implement the present invention. The LDS  104  is a TR-08 and GR-303 compatible local digital switch that employs distributed intelligence, process-oriented software, and coordinated autonomous computing elements to provide a flexible, modular, reliable and robust digital switching system. The LDS  104  provides a single platform for advanced services, including Integrated Services Digital Network (ISDN), Centrex, Custom Local Area Signaling Services (CLASS), custom calling, and Advanced Intelligent Network (AIN) capabilities. The LDS  104  also supports X.25 packet switched data communication and circuit switched data, and provides a gateway to local and long distance networks. The switching fabric, administration, message switching, and call switching functions are provided by the LDS  104 . 
     The AIN capabilities of the LDS  104  provide AIN switch software that enables the network provider to create, deploy, and change services to meet user&#39;s requests. The AIN software allows the LDS  104  to act as an AIN service switching point to communicate with service control points and intelligent peripherals. For example, the LDS  104  may be a 5ESS manufactured by Lucent Technologies or a DMS-100 manufactured by Nortel. In the WCS configuration illustrated in FIG. 1A, the NSP  106  acts a service control point, directing call processing on the LDS  104 . 
     The RDT  104  is a digital loop carrier terminal that supports the plain old telephone system (POTS), ISDN, high-speed transport, and special services such as private lines and private branch exchange (PBX) services. For example, the RDT  102  may be implemented by a SLC2000 manufactured by Lucent Technologies or an Access Node manufactured by Nortel. The RDT  102  interfaces, typically at a central office, with the LDS  104 . The RDT  102  provides the distribution of service interfaces between the LDS  104  and the user&#39;s premises, extending the digital access network. 
     The NSP  106  provides VAP  103 A,  103 B control, including mobile station and mobility management, call control, and feature applications. VAPs  103 A,  103 B are micro-cellular base stations or radio ports that support the IS-136 air interface with IS-136 mobile stations such as digital TDMA cellular/PCS (personal communications services) units  101 A,  101 B. The VAPs  103 A,  103 B support plug-and-play operations by connecting to the RDT  102  via standard open interfaces such as the ISDN basic rate interface (BRI) lines, typically using 2B+1D signaling protocol as is known in the art. 
     The IS-136 air interface standard is the EIA/TIA Interim Standard, also known as the North American or U.S. TDMA standard, that addresses digital cellular and PCS systems employing time division multiple access (TDMA). The IS-136 standard was developed to provide very flexible technical, service and investment options for subscribers and operators. IS-136 specifies a DCCH (Digital Control Channel) to support new features controlled by a digital signaling and control channel between a cell site (e.g., radio base station) and terminal equipment (e.g., mobile station). The IS-136 air interface between the VAPs  103 A,  103 B and the mobile stations  101 A,  101 B can support voice and messaging applications. The mobile stations  101 A,  101 B may be, but are not limited to, a terminal or a typical wireless phone having a keypad, display screen, and an alarm generator for generating a ringing or tone sound. 
     The present invention is implemented in the above system by cellular or personal communications service (PCS) mobile stations  101 A,  101 B. 
     FIG. 1B also includes POTS  108  and ISDN  109 , which may be utilized as described above. The WCS offers a wireless access system with Centrex to provide voice access and may either supplement existing wired Centrex service with wireless access or provide wireless-only stand-alone telecommunications services. WCS can connect the NSP  106  to a macro-cellular network to support integrated mobility functions including terminal handoff and personal roaming features. The WCS provides location and mobility management for a WCS&#39;s subscriber mobile station  101 A,  101 B inside the WCS service area. Cordless communication may be provided anywhere, anytime in the WCS service area. 
     FIG. 38 is a signal flow chart showing signaling flow steps for an illustrative embodiment implementing a call return in accordance with the present invention. FIG. 38 shows the call flow when the userjust requests to return the last incoming call. To facilitate understanding, the steps are partitioned into two general areas: a and b. 
     Section (a) of FIG. 38 shows how to display the called number to the user. The user dials a predetermined feature access code, e.g., *69, and presses the “send” button. An origination message, and optionally a serial number message, is sent by a mobile station MS  101 A,  101 B on a R-DCCH to a VAP  103 A,  103 B in accordance with the IS-136 standard. The VAP receives the origination message and sends an origination request, for example, where the dialed digit is *69, to the NSP (point  1 ) and starts a first timer TO 1 . The NSP receives the origination request message, identifies that the message is a feature request and utilizes the ID of the MS  101 A,  101 B to check whether the MS  101 A,  101 B is a valid, registered subscriber for the call return feature request. If the MS  101 A,  101 B is authorized for the call return feature, the NSP retrieves the digits of the last calling party number or directory number for returning the call (CallReturnDN) for the MS  101 A,  101 B and sends an origination ACK message (point  2 →point  3 ) with the display parameter that includes the CallReturnDN to the VAP and starts the timer TCR 1 . The TCR 1  timer is set to a predetermined time that permits Q.931 call processing, i.e., if this time was exceeded, the call would be terminated. 
     The VAP  103 A,  103 B stops the TO 1  timer and sends a Q.931 call setup signal to the LDS  104 . The LDS  104  sends an ISUP IAM signal to the PSTN/POTS  108  and may display the number on the MS&#39;s screen in accordance with the display function set forth in the IS-136 standard. However, if the VAP  103 A,  103 B has not received the origination ACK from the NSP  106 (point  3 ) before the expiration of the predetermined time that will allow pre-processing of the feature request, the VAP  103 A,  103 B will stop the TO 1  timer and clear the origination request record. 
     Next, as shown in (b), the VAP  103 A,  103 B sends a Q.931 Setup signal to the LDS  104 . Then the originating switch, the LDS  104 , sends an ISDN User Part Initial Address Message (ISUP IAM) to the destination switch of the public switched telephone network (PSTN/POTS  108 ) to reserve an idle trunk circuit from the originating switch to the destination switch. Then, the LDS  104  sends a Q.931 Call Proceeding signal to the VAP  103 A,  103 B. The VAP  103 A,  103 B sends an IS-136 digital traffic control (DTC) designation to the MS  101 A,  101 B. After the VAP  103 A,  103 B receives a DTC signal from the MS  10 A,  101 B, the destination switch of the PSTN/POTS  108  sends an ISDN user part Address Complete Message (ISDN ACM) to the originating switch, the LDS  104 , to indicate that the remote end of the trunk circuit has been reserved. Next, the LDS  104  sends a Q.931 alerting signal to the VAP  103 A,  103 B. The ringback tone is initiated by the PSTN/POTS  108  over the trunk to the originating switch, the LDS  104 . Then the PSTN/POTS  108  sends a ISDN User Part Answer Message (ISUP ANM) to the originating switch, the LDS  104 , which then sends a Q.931 connect signal to the VAP  103 A,  103 B. The VAP  103 A,  103 B then sends a Q.931 connect acknowledgement signal to the LDS  104  and a signal indicating success via an origination result message to the NSP  106 . The NSP  106  stops timer TCR 1 ,and a voice path is established. 
     Clearly the phone number for the incoming call must be known, e.g., not security-protected for the feature of the present invention to function. Thus, when the phone number of the incoming call is unknown or security-protected, the present invention may indicate that the phone number is unable to be displayed by a screen display, providing a voice prompt, providing a predetermined tone, or the like. 
     ISDN User Part (ISUP) call signaling is utilized in the call pre-processing for implementing the feature of the present invention. ISUP defines the protocol and procedures that are used to set-up, manage, and release trunk circuits carrying data and voice calls over the public switched telephone network, PSTN. ISUP is used for ISDN and non-ISDN calls, but calls that originate and terminate at a same switch do not use ISUP signaling. The ISUP message format includes information carried in the Signaling Information Field (SIF) which contains a routing label, a circuit identification code, and message type field. The ISUP Initial Address Message is sent in a “forward” direction by each switch needed to complete the circuit between the LDS and the destination switch of the PSTN until the circuit connects to the destination switch. The ISUP Address Complete Message is sent in the “backward” direction to indicate that the remote end of the truck circuit has been reserved. The originating switch then connects the MS  101 A,  101 B to the trunk to complete the voice circuit. The destination switch generates a ringing tone. The MS  101 A,  101 B user hears the ringing tone on the voice trunk. When the called party answers, the destination switch terminates the ringing tone and sends the ISUP Answer Message to the originating switch. The ISUP message format depends on whether the ANSI standard or the ITU-T standard is being implemented. 
     FIG. 39 illustrates one embodiment of steps for implementing a method for automatically returning an incoming call in a wireless communication system in accordance with the present invention. The steps include: receiving  3902  the incoming call by a wireless apparatus and automatically saving, where permitted, a phone number for the incoming call; and initiating  3904 , upon one of: a predetermined button/buttons being pressed or a predetermined verbal call return command being issued, automatic dialing of the phone number for the incoming call by the wireless apparatus. Where desired, the method may further include, between the steps of receiving the incoming call and initiating dialing the phone number for the incoming call, automatically displaying  3906  the phone number of the incoming call on a display. Also, where selected, where the phone number for the incoming call is unknown or security-protected, the method may include indicating  3908  that the phone number for the incoming call is unable to be displayed. Indicating that the phone number for the incoming call is unknown or unavailable, for example, due to security protection, may be implemented by any known method such as, for example, using a display, a voice prompt, or a predetermined tone. Where, after the step of receiving the incoming call, at least one more incoming call is received, the method may include automatically saving  3910  a phone number for each incoming call. Where selected, the method may also implement a step of automatically displaying  3912  the phone number of a most recent incoming call, and/or allowing the user, at his convenience, to display the phone number of a most recent incoming call by manually pressing a predetermined button or buttons  3914  or using a verbal command, thus conserving power expenditure for the display. Where selected, before initiating dialing the phone number of the most recently received call, the user may dispose  3916  of a first displayed phone number by moving at least one first displayed phone number to an end of a list of phone numbers of incoming calls received and/or may also transpose the first displayed phone number with a next phone number of the incoming calls received. Each of these two steps may be repeated as many times as desired. 
     As shown in FIG. 40, a wireless apparatus  4010  may be utilized for implementing the method of the present invention in a wireless communication system. Typically, the wireless apparatus  4010  is a wireless phone or another handheld wireless communications device such as, for example, a wireless digital assistant. The wireless apparatus includes a memory  4002 , for automatically saving, where permitted, a phone number for the incoming call received; and a wireless call return processor  4004 , coupled to the memory, for initiating, upon one of: a predetermined button/buttons  4006  being pressed or a predetermined verbal call return command being issued, automatic dialing of the phone number for the incoming call using the wireless apparatus. Where selected, the memory may store other predetermined information. For example, a user profile may be downloaded to the memory to permit authentication of the MS  101 A,  101 B at the VAP. Also, where a listing of usage or billing record is downloaded from the NSP for updating at the billing office, to avoid error, the billing record may be marked as “in use” by the NSP until the updated billing record has been sent to the NSP. Alternatively, the time for the current usage may be accumulated in the memory for a predetermined period and then forwarded to the NSP for incorporation into the user&#39;s billing record. The wireless apparatus may further include a display  4008 , coupled to the memory and the wireless call return processor, for automatically displaying, where permitted, the phone number of the incoming call on a display when the incoming call is received. The display  4008  operates as described above. 
     As shown in FIG. 38, a wireless communication system may include a wireless apparatus for automatically returning an incoming call. The wireless communication system includes a switched communications network (for example, the PSTN  108 ), a NSP  106 , a LDS  104 , a VAP  103 A,  103 B, and at least one MS  101 A,  101 B. Each of the elements is arranged to communicate as described above. 
     Alternatively, as shown in FIG. 41, the method of the present invention may be described as utilizing the steps of: configuring  4102  a wireless communication system to automatically return a previously received call; and returning  4104 , automatically, the previously received call. The configuration of the wireless communication system and the automatic return of the previously received call are accomplished as described for FIG.  38 . 
     FIG. 42 is a block diagram of one embodiment of a wireless communication platform for providing automatic wireless call return in accordance with the present invention. The platform includes: at least one mobile station  4202  and a micro-cellular base station controller  4204 . A micro-cellular base station means a base station in which components have been miniaturized to a degree such that the base station is mountable on a pole, shelf, or a wall. The micro-cellular base station controller  4204  is arranged to communicate wirelessly with the at least one mobile station  4202  and to receive an incoming call directed to the at least one mobile station, for, when the at least one mobile station  4202  is processing another call, automatically returning the incoming call in accordance with a predetermined scheme to provide automatic call return for the at least one mobile station. The predetermined scheme is the method described above. Where selected, the platform may further include a switching and database processor  4206  and a memory  4208 . The switching and database processor  4206  is coupled to the micro-cellular base station controller  4204  and a memory  4208  and is used for switching the incoming call according to the predetermined scheme to provide an automatic call return for the at least one mobile station, upon one of: a predetermined button/buttons being pressed or a predetermined verbal call return command being issued, by automatically dialing a phone number for the incoming call, wherein the phone number is stored in a database of the memory  4208 . The memory  4208  is coupled to the micro-cellular base station controller  4204  and the switching and database processor  4206 . Typically, the memory  4208  has a database stored thereon and is used for storing at least the phone number of the incoming call. Where desired, the memory  4208  may further store further information such as authentication information for the at least one mobile station or billing information for the at least one mobile station. 
     Although the present invention has been described in relation to particular preferred embodiments thereof, many variations, equivalents, modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims. 
     XIX. Automatic Callback 
     Technologies that facilitate wireless communication are emerging at an ever-faster rate. Such technologies are employed in end-user devices such as pagers, communication systems, and mail systems such as voice mail and email systems. In wireless communication systems, a need exists to provide a new service in the wireless environment for automatically calling back a phone number which is unavailable when the wireless user initiates a first call. A phone may be busy when the wireless user first calls, and busy again when the wireless user redials the number. It is clear that the wireless user&#39;s efficiency would be increased if the wireless user may be freed from having to redial the same busy number repeatedly in order to complete a call. 
     Present wireless handsets do not provide for automatic callback to free the user from having to redial, perhaps repeatedly, a number in order to complete a call. Clearly, there is a need for a system, wireless apparatus and method for providing automatic callback for a user in a wireless communication system when a called number is unavailable. 
     The present invention provides a system, wireless apparatus and method that provide an automatic callback functionality for wireless communication systems. The invention enables a wireless user to choose from a variety of modes for completing a call when the dialed number is busy. Rather than simply redialing the phone number an indeterminate number of times until the connection is made on his wireless device, the caller may press a button or give a verbal command to initiate an automatic callback feature. 
     An example is set forth below for implementing the present invention in a Wireless Centrex System (WCS). The WCS mobile station MS is not required to redial the same number repeatedly when he receives a busy signal. The dialing and checking procedure is performed by the WCS network, thus freeing the wireless user to perform other tasks. Typically, upon the called number becoming available, the WCS system informs the MS using a distinctive ringing and/or tone or a Short Message Service (SMS) message. Where the called number is available, but the MS already has an active call, the WCS system generates a voice prompt or special tone on the active call to notify the MS that the callback call is available. The MS may proceed as described below. 
     In one embodiment, the wireless user may activate the automatic callback feature by pressing a feature code, e.g., such as *66, and pressing “send” when a busy signal is received. Alternatively, after receiving the busy signal, the user can disconnect the call and then activate the callback feature. The WCS system sends a feature activation confirmation message to the MS, disconnecting the MS. A default timer is set to a predetermined time that determines the length of time that the feature is activated. Typically, the default is set to 30 minutes. The WCS system will automatically redial the number continuously (e.g., every 30 seconds) until a connection is made and notify the MS that the call is connected. If the predetermined default timer has expired (e.g., 30 minutes), then the WCS deactivates the feature and notifies the MS that the feature is deactivated. There may also be other scenarios wherein the WCS system will automatically be deactivated (e.g., when the mobile powers down). Where the dialed number remains busy after the predetermined time set on the default timer, the WCS system cancels the feature and sends a message to the MS notifying the wireless user that the call was unable to be completed. 
     Where desired, the wireless user may enter a predetermined deactivation code, e.g., *660, and push “send” to deactivate the feature. 
     In the example below, implementation of the present invention is accomplished using a wireless phone in a Wireless Centrex System  140 (WCS). The WCS  140  provides a private wireless access system that is unconnected to any public macro-cellular system and provides Centrex services. FIG. 1B shows a block diagram of an illustrative architecture of a WCS platform wherein the present invention may be utilized. The WCS platform includes a local digital switch  104  (LDS), a remote digital terminal  102  (RDT, e.g., Lucent Technologies SLC-2000), a network server platform  106  (NSP), voice access ports  103 A,  103 B (VAP) and a plurality of associated IS-136 digital time division multiple access (TDMA) cellular or personal communications service (PCS) mobile stations  101 A,  101 B which implement the present invention. The LDS  104  is a TR-08 and GR-303 compatible local digital switch that employs distributed intelligence, process-oriented software, and coordinated autonomous computing elements to provide a flexible, modular, reliable and robust digital switching system. The LDS  104  provides a single platform for advanced services, including Integrated Services Digital Network (ISDN), Centrex, Custom Local Area Signaling Services (CLASS), custom calling, and Advanced Intelligent Network (AIN) capabilities. The LDS  104  also supports X.25 packet switched data communication and circuit switched data, and provides a gateway to local and long distance networks. The switching fabric, administration, message switching, and call switching functions are provided by the LDS  104 . 
     The AIN capabilities of the LDS  104  provide AIN switch software that enables the network provider to create, deploy, and change services to meet user&#39;s requests. The AIN software allows the LDS  104  to act as an AIN service switching point to communicate with service control points and intelligent peripherals. For example, the LDS  104  may be a 5ESS manufactured by Lucent Technologies or a DMS-100 manufactured by Nortel. In the WCS configuration illustrated in FIG. 1A, the NSP  106  acts a service control point, directing call processing on the LDS  104 . 
     The RDT  102  is a digital loop carrier terminal that supports the plain old telephone system (POTS), ISDN, high-speed transport, and special services such as private lines and private branch exchange (PBX) services. For example, the RDT  102  may be implemented by a SLC2000 manufactured by Lucent Technologies or an Access Node manufactured by Nortel. The RDT  102  interfaces, typically at a central office, with the LDS  104 . The RDT  102  provides the distribution of service interfaces between the LDS  104  and the user&#39;s premises, extending the digital access network. 
     The NSP  106  provides VAP  103 A,  103 B control, including mobile station and mobility management, call control, and feature applications. VAPs  103 A,  103 B are micro-cellular base stations or radio ports that support the IS-136 air interface with IS-136 mobile stations such as digital TDMA cellular/PCS (personal communications services) units  103 A,  103 B. The VAPs  103 A,  103 B support plug-and-play operations by connecting to the RDT  102  via standard open interfaces such as the ISDN basic rate interface (BRI) lines, typically using 2B+D signaling protocol as is known in the art. 
     The IS-136 air interface standard is the EIA/TIA Interim Standard, also known as the North American or U.S. TDMA standard, that addresses digital cellular and PCS systems employing time division multiple access (TDMA). The IS-136 standard was developed to provide very flexible technical, service and investment options for subscribers and operators. IS-136 specifies a DCCH (Digital Control Channel) to support new features controlled by a signaling and control channel between a cell site (e.g., radio base station) and terminal equipment (e.g., mobile station). The IS-136 air interface between the VAPs  103 A,  103 B and the mobile stations  110  can support voice and messaging applications. The mobile stations  101 A,  101 B may be, but are not limited to, a terminal or a typical wireless phone having a keypad, display screen, and an alarm generator for generating a ringing or tone sound and translation between text and speech. 
     The automatic callback functionality of the present invention is implemented in the above system by cellular or personal communications service (PCS) mobile stations  101 A,  101 B. 
     FIG. 1B also includes POTS  108  and ISDN  109  interfaces for connecting analog and ISDN phones, respectively. The WCS offers a wireless access system with Centrex to provide voice access and may either supplement existing wired Centrex service with wireless access or provide wireless-only stand-alone telecommunications services. WCS can connect the NSP  106  to a macro-cellular network to support integrated mobility functions including terminal handoff and personal roaming features. The WCS provides location and mobility management for a WCS&#39;s subscriber mobile station  101 A,  101 B inside the WCS service area. Cordless communication may be provided anywhere, anytime in the WCS service area. 
     Though not shown in FIG. 43, the WCS system determines whether the user may validly request the automatic callback feature functionality. Upon receiving the origination request message, the NSP  106  analyzes the dialed digits and identifies that the automatic callback feature has been requested. The NSP  106  also checks the Wireless Centrex System Directory (WCSD) via the Mobile Identification Number (MIN) to determine if the MS  101  is authorized for the automatic callback feature requested. If the validation is successful, the NSP  106  uses the MSID to last dialed DN mapping to retrieve the DN that was dialed by the MS  101  previously, sends an origination NACK with the last dialed DN message to the VAP  103 . 
     The VAP  103  sends an IS-136 Reorder/Intercept message to the MS  101  informing the user that the automatic callback feature is activated for the last dialed DN. If the validation is not successful or the last dialed DN is not known, the NSP  106  sends an originating NACK message with reject information to the MS  101 . The VAP  103  sends an IS-136 Reorder/Intercept message to the MS  101  informing the user that the automatic callback feature was not activated. Feature Activation/Deactivation is described more fully in Section IX herein. 
     FIG. 43 shows a preferred embodiment for signaling flow in accordance with the automatic callback functionality of the present invention. As shown in (a), the NSP  106  sets the feature activation timer for a predetermined length of time (e.g., 30 minutes) when the feature is activated. The NSP will continuously initiate calling the Last Dialed DN for every predetermined time (e.g., 30 seconds) by sending a StartAutoCallBack message including the Mobile Station IDentification code (MSID) and the Last Dialed Directory Number (LastDialedDN) to the VAP  103  and starts the TAC 1  timer. The VAP  103  initiates the call origination process by sending a Q.931 setup message to the LDS  104  utilizing the LastDialedDN. 
     As described below, ISDN User Part (ISUP) call signaling is utilized in the call pre-processing for implementing the feature of the present invention. ISUP defines the protocol and procedures that are used to set-up, manage, and release trunk circuits carrying data and voice calls over the public switched telephone network, PSTN. ISUP is used for ISDN and non-ISDN calls, but calls that originate and terminate at a same switch do not use ISUP signaling. The ISUP message format includes information carried in the Signaling Information Field (SIF) which contains a routing label, a circuit identification code, and message type field. The ISUP Initial Address Message is sent in a “forward” direction by each switch needed to complete the circuit between the LDS and the destination switch of the PSTN until the circuit connects to the destination switch. The ISUP Address Complete Message is sent in the “backward” direction to indicate that the remote end of the trunk circuit has been reserved. The originating switch then connects the MS to the trunk to complete the voice circuit. The destination switch generates a ringing tone. The MS user hears the ringing tone on the voice trunk. When the called party answers, the destination switch terminates the ringing tone and sends the ISUP Answer Message to the originating switch. The ISUP message format depends on whether the ANSI standard or the ITU-T standard is being implemented. 
     Thus, as shown in FIG. 43, portion (a), upon initiation of the automatic callback feature, the originating switch, the LDS  104 , sends an ISDN User Part Initial Address Message (ISUP IAM) to the destination switch of the public switched telephone network (PSTN)  125  to reserve an idle trunk circuit from the originating switch to the destination switch. Then, the LDS  104  sends a Q.931 call proceeding signal to the VAP  103 . The destination switch of the PSTN  125  then sends an ISDN user part Address Complete Message (ISDN ACM) to the originating switch, the LDS  104 , to indicate that the remote end of the trunk circuit has been reserved. Next, the LDS  104  sends a Q.931 alerting signal to the VAP  103 , and the VAP  103  sends a StartAutoCallback Proceeding message to the NSP  106  to notify the NSP  106  that an alerting message have been received from the LDS  104  indicating that the dialed DN is now alerted and waiting for an answer. If the destination user is still busy when the call is attempted, the destination switch  125  returns an ISUP REL (release) message to LDS  104 , indicating that the called user is busy. The LDS  104  initiates Q931 call clearing to the VAP. The VAP notifies the NSP of the failure. The NSP resets its timer and waits for a predetermined time (e.g., 30 seconds) before initiating the callback procedure again. 
     Continuing the description of FIG. 43, in portion (b), upon receiving the StartAutoCallBack Proceeding message from the VAP  103 , the NSP  106  cancels timer TAC 1  and sends a Page Request message (MSID, Signal) to the VAP  103 . The VAP will then send an IS-136 Page to the MS  101 . The MS  101  sends an IS-136 Page Response to the VAP  103 . Then, the VAP  103  sends the page response to the NSP  106 . The NSP  106  sets timer TAC 2  to wait for completion of the call. The VAP  103  also sends an IS-136 Digital Traffic Channel (DTC) designation to the MS  101 . The MS  101  then tunes to the designated DTC. The VAP  103  sends an IS-136 Alert with information (Signal) to the MS  101 . Note the signal can be a special tone indicating to the MS user that the call is their automatic callback call. The MS  101  sends an IS-136 Mobile ACK, then an IS-136 Connect signal, to the VAP  101 . The ringback tone is initiated by the PSTN  125  over the trunk to the MS  101 . Then the PSTN  125  sends a ISDN User Part Answer Message (ISUP ANM) to the originating switch, the LDS  104 , which then sends a Q.931 connect signal to the VAP  103 . The VAP  103  then sends a Q.931 connect acknowledgement signal to the LDS  104  and a signal indicating success via an origination result message (Auto Callback Result (Successful)) to the NSP  106 . The NSP  106  stops timer TAC 2 , and a voice path is established. 
     A predetermined time is set on timer TAC 1  and timer TAC 2  such that Q.931 and IS-136 call processing may take place. If the predetermined time is exceeded, the NSP  106  will initiate procedures to clear the call. Where the predetermined time set on the timer TAC 1  or TAC 2  has expired, or the StartCallBack Result signal indicates failure, the NSP  106  sends a Cancel AutoCallBack message to the VAP  103  and deactivates the automatic callback feature for the MS  101 . In addition, the NSP  106  can send a short message to the MS  101  to indicate that the automatic callback feature has been cancelled or the time for the automatic callback has expired. Where desired, the MS  101  may re-request that the automatic callback feature be activated either by redialing the feature code or by a voice command. 
     FIG. 44 is a signal flow chart showing a preferred embodiment of signaling flow when the MS moves from an original serving VAPo to a new VAPn before a call is connected. The MS  101  activates the Automatic Callback feature and moves from the original VAPo  103 A to another VAPn  103 B. The VAPn  103 B sends a Handoff Result message to the NSP  106  to indicate that handoff has occurred. The NSP  106  sends Cancel AutoCallBack message containing the MSID and the LastDialedDN to the VAPo  103 A and starts a TACBC 1  timer. If the VAPo has already initiated a Q.931 call setup process to Last Dialed DN, then the VAPo initiates a Q.931 call release procedure to clear the call attempt. The VAPo  103 A sends a Cancel AutoCallBack Ack message to the NSP  106 . The NSP  106  stops the TACBC 1  timer and assumes Automatic Callback procedures and signaling exchange with VAPn. If the NSP  106  timer TACBC 1  expires before receiving the Cancel AutoCallBack Result message from the VAPo or the cause for cancellation is not indicated as successful, the NSP  106  continues the new Automatic Callback feature with the VAPn  103 B. 
     The WCS may be configured to offer service within a local access environment. While the IS-136 standard is used to illustrate the best mode for carrying out the invention, the invention is not limited to use in the IS-136 standard. The invention is also applicable to other cellular and/or PCS systems. 
     FIG. 45 is a flow chart showing one embodiment of steps of a method in accordance with a preferred embodiment of the present invention. The method provides for, where a number called by a wireless user is busy, automatically redialing the call in a wireless communication system, and includes the steps of: A) placing  4502  an outgoing call by a wireless apparatus and automatically saving, where permitted, a called phone number for the outgoing call; and B) initiating  4504 , upon one of: a predetermined button/buttons being pressed or a predetermined verbal callback command being issued, automatic redialing of the phone number for the outgoing call by the wireless apparatus. Where desired, the method may further include, upon being connected after redialing, automatically displaying  4506  the phone number for the outgoing call on a display. 
     Where selected, the method may further include, after placing a plurality of outgoing calls and saving the called phone numbers, where the called phone numbers are displayed, disposing  4508  of a first displayed phone number. A displayed phone number may be disposed of by one of: moving  4510  at least a first displayed phone number to an end of a list of phone numbers of outgoing calls or transposing  4512  the first displayed phone number with a next phone number of the outgoing calls. 
     Where an automatic callback call is received  4514 , the method may include one of: pressing a button/giving a verbal command  4516  to speak immediately with the individual returning the call; pushing a button/giving a verbal command  4518  to place a call in progress on hold and speak immediately with the individual returning the call; and pushing a button/giving a verbal command  4520  to implement a functionality of placing the incoming call on hold and playing a prerecorded message that explains that the call is being put on hold for a short period of time. The callback call may be terminated when the wireless user does not answer within a predetermined time. 
     FIG. 46 is a block diagram of a preferred embodiment of a wireless apparatus that may be utilized for implementing the method of the present invention in a wireless communication system. The wireless apparatus  4610  may include: a memory  4602 , for automatically saving a phone number that was busy when called and, if selected, phone numbers of incoming calls; and a wireless automatic callback processor  4604 , coupled to the memory, for initiating a wireless callback communication, upon one of: a predetermined button/buttons  4606  being pressed or a predetermined verbal callback command being issued, by automatically redialing the phone number for the call. The wireless apparatus may also include a display  4608 , coupled to the memory  4602  and the wireless automatic callback processor  4604 , for automatically displaying the phone number of the redialed call, and/or a phone number of an incoming call, where permitted, on a display when the incoming call is received. Where the phone number for the incoming call is one of: unknown or security-protected, the display may indicate that the phone number for the incoming call is unable to be displayed. Alternatively, a voice prompt or predetermined tone may indicate that the phone number for the incoming call is unable to be displayed. 
     Where selected, the memory may automatically save a phone number, where permitted, for a plurality of incoming calls and the display may provide for automatic display, where permitted, of a phone number of a most recent incoming call. Alternatively, the wireless automatic callback processor may dispose of a first displayed phone number by moving at least one first displayed phone number to an end of a list of phone numbers of incoming calls received or transposing the first displayed phone number with a next phone number of the incoming calls received. The two preceding procedures may be repeated as desired. 
     Typically, the wireless apparatus is a wireless phone or another handheld wireless communications device such as, for example, a personal digital assistant. 
     A wireless communication system may include a wireless apparatus described above for automatically redialing a call where a phone number for the call is busy when the wireless user places the call. The system may operate as described above or in an equivalent fashion. For example, the system may include: a switched communications network, coupled to at least a first remote digital terminal RDT  102 ; at least a first network server platform NSP  106 , coupled to at least a first local digital switch LDS  104 ; the at least first LDS  104 , coupled to the at least first RDT  102  and the at least first NSP  106 , and, where selected, to a voice message system VMS  107 ; the at least first RDT  102 , coupled to the at least first LDS  104 , at least a first voice access port VAP  103 A,  103 B; the at least first VAP  103 A,  103 B, coupled to the at least first RDT  102  and arranged to communicate with at least a first mobile station MS  101 A,  101 B; the at least first mobile station MS  101 A,  101 B, arranged to communicate with the at least first VAP  103 A,  103 B, wherein the at least first MS  101 A,  101 B includes the wireless apparatus for automatically redialing the number, and wherein the switched communications network, the at least first NSP  106 , the at least first LDS  104 , the at least first RDT  102 , the at least first VAP  103 A,  103 B and the at least first MS  101 A,  101 B utilize a predetermined scheme to provide automatic callback for the wireless apparatus. 
     FIGS. 47A-47C represent a flow chart showing another embodiment of steps for implementing the automatic callback feature of the present invention wherein the intelligence of the automatic callback feature is in the VAP rather than in the NSP as previously shown in FIG.  43 . FIG. 43 illustrates network centric intelligence (i.e., NSP) whereas FIGS. 47A-47C illustrate a distributed intelligence embodiment. FIG. 47A illustrates steps during call establishment/activation; FIG. 47B illustrates steps for the NSP procedure. FIG. 47C illustrates steps for the VAP procedure. The automatic callback (ACB) feature frees the user from re-dialing the same busy number repeatedly. The wireless user is typically alerted by a special ringing tone when the called party becomes available. when the NSP  106  stores  4702  a last dialed digit for an automatic callback subscriber, the NSP  106  determines  4704  whether the automatic callback feature can be activated by the wireless user. When the automatic callback feature cannot be activated and validated, the NSP  106  rejects  4706  the automatic callback request and informs the user. Where the automatic callback feature can be activated and validated, the NSP  106  does so and starts a timer (in one embodiment the timer is set for 30 minutes) and informs the VAP  103 A,  103 B to start the automatic callback process. Then, the VAP  103 A,  103 B start  4710  the automatic callback process, and the NSP  106  starts  4712  the automatic callback process. While the VAP  103 A,  103 B is processing the automatic callback procedure, the following can occur: 
     1. The MS moves to another VAP (either via handoff or location registration), and the NSP informs the former VAP to cancel the automatic callback and the new VAP to start automatic callback. 
     2. The MS powers down, and power down registration is sent to the NSP. The NSP cancels the automatic callback for the VAP and for itself. 
     3. The MS becomes busy while the VAP is completing the call to the MS and the wireless user does not answer the call. The VAP releases the call, cancels the automatic callback and informs the NSP. The NSP determines that the procedure failed because the MS is busy and informs the VAP to restart the automatic callback procedure. 
     The above scenarios are valid only during the time period when the NSP has instructed the serving VAP to initiate the automatic callback procedure and the VAP fails when it attempts to page the MS. 
     There are typically two controlling timers. Clearly, more timers may be utilized, and various times for the timers may be predetermined by the user. In the embodiment shown, a 30 minute (T 1 ) timer is used in the NSP and a 30 second (T 2 ) timer is used on the VAP side. FIG. 47B illustrates steps for one embodiment implementing the NSP  4712  procedure. T 1  is the master timer. The NSP determines  4718  whether T 1  has expired. When the master timer has expired  4720 , the NSP informs the VAP to cancel the ACB and cancels ACB on the NSP side. Where T 1  has not expired, the NSP determines  4722  whether it has received a result message (msg) from the VAP. Where no result message has been received, the NSP returns to checking whether T 1  has expired  4718 . Where a result message has been received, the NSP determines  4724  whether the cause for receiving the result message is a successful call. Where the automatic callback has been successful, the NSP cancels the timer (T 1 )  4726 . Where the automatic callback has been unsuccessful, the NSP informs  4728  the serving VAP to start the automatic callback procedure. 
     FIG. 47C illustrates one embodiment of steps for the VAP  4710  procedure. T 2  on the VAP side will only control the call establishment time for the VAP. The VAP will try every 30 seconds to establish a call with the remote user until the call is successfully connected or the procedure is cancelled. Typically, for example, the VAP may notify the NSP that the VAP plans to utilize the B channel for call establishment by sending a BchnlStatus message. The VAP will start T 2  (the 30 second timer)  4732 . The VAP determines  4734  whether 30 seconds has expired. If 30 seconds has not yet expired, the VAP continues to check whether the 30 seconds has expired  4734 . If the 30 seconds has expired, the VAP determines whether the NSP has notified the VAP to stop/cancel  4736  the automatic callback procedure. If the NSP has notified the VAP to stop or cancel the automatic callback procedure, the VAP cancels/stops  4738  the automatic callback procedure. If the NSP has not notified the VAP to stop or cancel the automatic callback procedure, the VAP determines  4740  whether there are resources available to complete the call. If resources are not available, the VAP returns to the step of starting T 2   4732 . If resources are available, the VAP initiates  4742  the call to the destination user. In the diagram and similarly for FIGS. 47A and 47B, a circle  4744  simply serves to show the connection between the top portion of FIG. 47C with the bottom portion of FIG.  47 C. The call setup procedure will indicate to the VAP whether the PSTN user is still busy. If the PSTN user is still busy, the VAP releases  4748  the call, which in this example, releases the B channel and the VAP resets the T 2  timer  4732 . If the PSTN user is no longer busy, the VAP pages  4750  the MS. Then, the VAP determines  4752  whether the MS has responded. If the MS has not responded, the VAP releases the call, sends notification to the NSP and cancels  4764  the automatic callback procedure. If the MS has responded, the VAP connects  4754  the call to the MS. Then, the VAP determines  4756  whether the call is connected. If the call is connected, the VAP cancels  4762  the automatic callback procedure and informs the NSP. If the call is not connected, the VAP releases  4758  the call, which in this example, releases  4760  the B channel and the VAP resets the T 2  timer  4732 . 
     Thus, when the T 2  timer expires, the VAP first checks whether the MS is idle and then retries to establish the call. If the remote user is busy, VAP will reset the timer. If the remote user is idle VAP will attempt to terminate the call to the MS. If the VAP fails to establish a call with the MS (i.e., the MS is busy, powered down, moved out of coverage area) VAP will immediately cancel ACB on the VAP and inform NSP. The NSP then determines the status of the ACB procedure (explained in detail above). 
     FIG. 48 is a flow chart showing another embodiment of steps in accordance with the method of the present invention. The method includes the steps of: configuring  4802  a wireless communication system to automatically redial a phone number of a call when the phone number called by a wireless user is busy; and redialing  4804 , automatically, the phone number when the phone number called by the wireless user is busy. 
     FIG. 49 is a block diagram of one embodiment of a wireless communication platform for providing wireless automatic callback in accordance with the present invention. The wireless communication platform includes at least one mobile station  4902  and a micro-cellular base station controller  4904  for wireless automatic callback that is arranged to communicate wirelessly with the at least one mobile station. When a number called by the at least one mobile station  4902  is busy, the micro-cellular base station controller  4904  for wireless automatic callback automatically redials the number to provide automatic callback for the at least one mobile station. The wireless communication platform may further include a switching and database automatic callback processor  4906  for wireless automatic callback that is coupled to the micro-cellular base station controller  4904  for wireless automatic callback and a memory  4908 . The switching and database automatic callback processor  4906  provides processing for wireless automatic callback for the at least one mobile station upon one of: a predetermined button/buttons being pressed or a predetermined verbal callback command being issued, by automatically redialing the number. The memory  4908  is coupled to the micro-cellular base station controller  4904  for wireless automatic callback and to the switching and database automatic callback processor  4906 . The memory  4908  has a database for storing at least the number redialed. Where selected, the memory  4908  may further store information for authentication and/or billing information for the at least one mobile station. 
     Although the present invention has been described in relation to particular preferred embodiments thereof, many variations, equivalents, modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims. 
     XX. Speed Calling 
     The speed calling feature allows a subscriber to compile a list of phone numbers in which each phone number is associated with a unique speed calling code. A subscriber can provision a unique speed calling code for one or more telephone numbers. When an MS user enters a valid speed calling code, the WCS system will complete the call using the telephone number in the speed calling list corresponding to the speed calling code entered. 
     There are several ways a subscriber can provision a telephone number for speed calling. For example, the user may access the Internet or a web-based interface such as a WCS web site and input and update a list of phone numbers having speed calling. Also, the subscriber may contact a customer care center representative by phone and verbally communicate the numbers through any type of communications unit (e.g., cell phone, landline phone, wireless palm top computer phone, etc.). Alternatively, a user may be directed through an automated phone menu to input the numbers by use of a communications unit keypad or voice recognition system. 
     According to one embodiment, the user may provision the speed calling telephone numbers through the WCS system. In this regard, the subscriber may activate the feature by entering a feature activation code, a speed calling code (e.g., 1-30) followed by a phone number (e.g., *75*1#5555151) into the keypad of MS  101 A and then pressing the “send” button. Actuation of the “send” button sends the feature activation message to the WCS system (e.g., NSP  106 ). The WCS system then may acknowledge activation of the feature, by retuning a short message to the MS  101 A, or alternatively an aural communication, including identity of the feature activated, the speed calling code and phone number, for example. In addition, a message indication that a call origination request has been rejected can be used to provide feature activation/deactivation status  1 . 
     In a further modification, the speed calling code may be automatically assigned such as with the first available speed calling code. Thus, the subscriber might send the feature activation code followed by the telephone number (e.g., *75*#5555151) to the WCS system. In this instance, when the subscriber fails to enter a speed calling code, a speed calling code may be automatically assigned to the telephone number. Illustratively, if thirty codes are available (code numbers  1 - 30 ) and code numbers  1 ,  2 ,  4  and  7  have been assigned, the system can assign the next available code, which would be code number  3  to the telephone number input by the subscriber. If all available speed calling codes are assigned, the system can send a short message or aural message indicating the same, or can send status information with a message indicating that a call origination request has been rejected. Also, the subscriber may enter a code requesting the system to identify the telephone number associated with a speed calling code. 
     To delete a phone number from the speed call list, the subscriber may overwrite the existing phone number assigned to a speed call code with another number. Alternatively, the subscriber may enter a feature deactivation code followed by the telephone number and press the “send” button. Also, the subscriber may deactivate the speed calling codes for all numbers by entering a global feature deactivation code and the “send” button on the MS  101 A. A more detailed discussion of feature activation and deactivation is provided at other places in the instant description, for example at section IX, above. 
     To implement the speed call feature, the subscriber dials the speed calling code (e.g., *1) for the desired telephone number and presses the “send” button on MS  101 A. If the speed call code entered is unassigned, an error message will be returned to the subscriber by a short message or otherwise. 
     According to an illustrative embodiment of the invention, the speed call list may be stored in a memory in the NSP  106  or a memory location accessible to the NSP  106 . The list may include any amount of numbers depending on the capacity of the memory employed. In one embodiment, up to thirty numbers may be defined to have a unique speed call code and the size of the telephone numbers can range from 1-17 digits. 
     FIG. 50 provides an exemplary call flow diagram for implementing the speed call feature according to an illustrative embodiment of the present invention. While the IS-136 standard is used to illustrate one implementation of the present invention, it should be understood that the present invention is applicable to other cellular or PCS systems. 
     When a WCS subscriber wants to place a call utilizing speed calling, the subscriber inputs the speed calling code *n, where n is the code and actuates the “send” button. In response, MS  101 A sends an IS-136 origination [DN=*n] message  5002  to a VAP  103 A at which the MS  101 A is registered. Also, the MS  101 A sends an IS-136 serial number message  5004  to the VAP  103 A. In response, the VAP  103 A sends a proprietary origination request message (Origination Request [dialed digit=*N])  5006  to the NSP  106  and starts timer T 01 . The NSP  106  receives the origination request message  5006  and identifies that a speed call attempt is being made. 
     The NSP  106  then determines whether MS  101 A subscribes to the speed call feature by comparing the MIN of MS  101 A with an authorized subscriber list maintained in the WCSD. If the MS  101 A is not authorized for the speed call feature, then the NSP  106  sends the VAP  103 A an origination non-acknowledgment (NACK) message (not shown) and indicates that the MS  101 A does not subscribe to the speed call feature. The timer T 01  is canceled and the VAP  103 A then notifies the MS  101 A subscriber through a short message or aural message that it does not subscribe to the speed call feature. 
     If the MS  101 A is authorized for the speed call feature, then the NSP  106  determines whether the speed call code input by the subscriber corresponds to a telephone number. If no number corresponds to the entered speed call code, a NACK message is sent to the VAP  103 A including a DN unavailable message and the timer T 01  is canceled. The DN unavailable message is then delivered by the VAP  103 A to the MS  101 A. 
     If the MS  101 A is authorized fro the speed call feature and a phone number corresponds to the speed call code entered, the NSP retrieves the telephone number associated with the speed dialing code from the speed dial list. Then, the NSP  106  sends an origination acknowledgement message  5008  (origination ACK (SpeedDial DN)) including the telephone number to the VAP  103 A and starts the timer TSC 1 . Responsive to the origination acknowledgement message  5008 , the VAP  103 A cancels timer T 01  and initiates a Q.931 call set up procedure using the telephone number corresponding to the speed dial code, i.e., speed dial DN. If the T 01  timer expires before the VAP  103 A receives the origination acknowledgement message  5008 , the VAP  103 A sends an IS-136 reorder/intercept message (not shown) to MS  101 A including information about what went wrong similar to when the VAP  103 A receives an origination NACK message. 
     The call set up procedure is similar to call set up procedure described elsewhere in this application, but will be described here for completeness. To set up the call, the VAP  103 A reserves an RF DTC channel and sends a Q.931 setup [speed dial DN] message  5010  to the LDS  104 . The LDS  104  then examines the speed dial DN in the Q.931 setup message  5010  and sends an ISUP IAM message  5012  to a far end switch in the PSTN  125  for end-to-end connectivity. Also, the LDS  104  sends a Q.931 call proceeding message  5014  to the VAP  103 A. The VAP  103 A then sends an IS-136 Digital Traffic Channel (DTC) Designation  5016  message to the MS  101 A so that MS  101 A may tune to the designated traffic channel. MS  101 A informs VAP  103 A that it is using the designated DTC by responding with an MS on DTC message  5018 . The VAP  103 A then detects that the MS  101 A is tuned to designated traffic channel, and cuts through the voice path  5034  between the RF DTC channel and an ISDN B channel. 
     The destination switch in the PSTN  125  sends an ISUP ACM message  5020  to the LDS  104 . In response, the LDS  104  sends a Q.931 alerting message  5022  to VAP  103 A. Next, a ringback tone  5024  is delivered to the MS  101 A from the destination switch. Also, the PSTN  125  sends an ISUP ANM message  5026  to the LDS  104 . Following receipt of the ISUP ANM message  5026 , the LDS  104  sends a Q.931 connect message  5028  to the VAP  103 A, removes the ringback tone  5024 , and cuts through the voice path  5034 . The VAP  103 A then sends a Q.931 connect ACK message  5030  back to the LDS  104  to acknowledge the connection. Responsive to the Q.931 connect ACK message  5030 , the VAP  103 A sends origination result [success] message  5032  to the NSP  106  for billing and other OAM&amp;P purposes. At this point, voice path  5034  has been established and the call proceeds between the MS  101 A and the party called using the speed call code. 
     While the above description relates to an example of speed calling for a party coupled to a PSTN, it should be understood that a speed calling code may be set up for any party which a subscriber may call including, but not limited to, a WCS subscriber, a landline subscriber, and a cellular subscriber. Also, multiple phone numbers can be assigned to a single unique speed calling code such that entry of the speed calling code will initiate a call involving parties at each of the multiple phone numbers in a conference call. Reference is made herein to the description of conference calling in Section XXI below, which can be modified to provide for a speed call code to originate a three-way call, for example. 
     XXI. Conference Calling 
     A. Adding A Party To An Existing Call 
     The conference call feature/function allows a MS  101  user to talk with two or more parties at the same time. Once the MS  101  user is on a first active call, he can enter a feature code, for example by keying in *33# on the MS  101  keypad followed by a third party&#39;s DN (conference with DN) and then pressing a transmit key, for example, the “send” button, to initiate a conference call. Once validated by the WCS network determining that the MS- 101  user is authorized to use the conference calling feature/function, an announcement is provided, for example, a voice prompt or a special tone will be heard by the MS  101  user (and optionally to the second party to an active call) indicating that a conference call connection (e.g., Three-Way Calling) has been requested. After the third party answers, the MS  101  user may then enter another code, for example by pressing the “send” button on the MS  101 , to begin the multi-party conference call conversation. 
     The following detailed description of the conference call feature/function is described in terms of a three way call for ease of explanation and because one typical local digital switch has three way switches for each wireline. However, one skilled in the art will recognize that a switch having greater than three possible line connections (i.e., more than a three-way switch) may be provided in the local digital switch, e.g., a six way switch. Therefore, the conference call feature/function, although described in specific embodiments below illustrating three-way calling, is also applicable to conference calls having more than three parties by repeating portions of the conference call initiation and setup procedures. 
     Further, the signal flows used for Three-Way calls in this document are directed to comply with the Lucent 5ESS local digital switches and may apply to other local digital switches, such is the Nortel DMS-100 local digital switches, with or without modifications. Since the interface between LDS  104  and the VAP  103  is based on standard Q.931 messages it is supported by all LDSs. So, with minimum changes (if needed), the exemplary call flow described with reference to the Lucent 5ESS would work with other LDSs such as the Nortel DMS-100. 
     The conference call feature/function provides an MS  101  user with a convenient and user friendly method of creating a multi-party call. Once the MS  101  user has established an active call, for example a two-way call, with one or more other parties the MS  101  user is free to initiate adding a person for a conference call. First, while on an active call, the MS  101  user may indicate to the other party that a Three-Way call will be requested. After entering the conference call feature code, e.g., pressing the *33#, followed by the third party&#39;s DN, the MS  101  user will transmit this information to the WCS by, for example, pressing the “send” button. The existing second party is then put on hold and the MS  101  user initiating the conference call feature/function will be provided an announcement, for example, a voice prompt or a special tone on the MS  101  indicating the Three-Way call activation is now proceeding. The voice prompt or special tone may also be provided to the other party, or alternatively other audible sounds may be provided to the other party such as music. 
     If the MS  101  user initiates the conference call feature/function during an already active three-way call they initiated, and the LDS  104  is equipped with a switch that is capable of handling connection of another party (i.e., more than a three-way switch), the request for another conference call initiation will be honored and a similar connection procedure will ensue. However, if the LDS  104  is equipped with only a three-way switch, the request for another conference call initiation to add an additional party will be rejected and an appropriate notification (e.g., an announcement) of the limitation to a three-way call will be provided to the MS  101  user. Furthermore, if the MS  101  user transmits an empty message by, for example, pressing the “send” button before the original call is put on hold, the NSP  106  will ignore it. 
     When the call goes through to the third party, the MS  101  user who initiated the conference call will hear the ringing tone. If the third party answers, the MS  101  user can press a key on the MS  101 , for example, the “send” button, (within a certain time period) to retrieve the held call(s) and complete the conference call (e.g., Three-Way) connection. In one alternative embodiment, the MS  101  cannot disconnect a third party who answers without first establishing a three-way connection. If the third party answers and the initiator presses a transmit key, for example, the “send” button once, to set up a three-way call but the original two-way call could not be retrieved for some reason (e.g., the party to the original two-way call on hold has hung up), the two-way call with the second called party will continue. An indicator, for example a voice prompt, indicating that the party on hold can not be connected may be provided to the MS  101  user who initiated the conference call feature/function. 
     If the third party answers and disconnects before the MS  101  user can establish a conference call (e.g., a three-way call), the MS  101  user can again transmit a message, by for example pressing a the “send” button once, and retrieve the original call. Further, if the connection to third party fails as a result of the switch being unable to connect to the third party (rather than the third party is busy or is not answering the phone), the MS  101  user can enter a code message, for example, press the “send” button once, to retrieve the original call placed on hold. On the other hand, if the third party&#39;s line is busy or the third party does not answer the phone, the MS  101  can enter another code message, for example the MS  101  can press the “send” button twice, to disconnect the second leg of the call and retrieve the original call on hold. Once again, if the original called party has already disconnected, an indication that the original called party is disconnected may be provided, e.g., an announcement such as a voice prompt may be played to the MS  101  user. 
     Furthermore, if the third party&#39;s voice mail answers, the three-way call is assumed to be complete. The MS  101  user may enter a code message, for example they can press the “send” button once, within a certain amount of time and establish a three-way conference. In one alternative embodiment the initiator can disconnect from the third party voice mail and end the conference call by pressing the “send” button twice only after the three-way call has been established. Thus, in this embodiment the MS  101  conference call initiator must establish the conference call connection by retrieving the original call in order to disconnect from the third party&#39;s voice mail. 
     At any time during an established conference call, the MS  101  user can enter a feature code message, for example by pressing the “send” button twice quickly (within a certain amount of time, e.g., within a few seconds) and disconnect the last added call. To end all calls the MS  101  user can enter another code, for example the initiator may just press the “End” button. 
     Referring now to FIGS. 51 and 52, a discussion of various scenarios for a preferred embodiment having a three-way conference call is illustrated using a process flow chart. In a first instance, an MS  101  user calls another party, either another MS  101  user or a PSTN user, and establishes an active two-way call in progress at step  5101 . During the active two-way call the MS  101  initiates a three-way conference call by entering a feature code and a conference to directory number (DN) of the party to be added (e.g., third party), and then press a process initiation key by pressing, for example, the “send” key on the MS  101  as shown in step  5102 . In the next step, feature validation decision step  5103 , the NSP  106  determines whether the MS  101  user is authorized to use the conference call feature/function (i.e., the MS  101  user subscribes for the feature), and if so, notifies the VAP  103  to go forward with the conference call set up. However, if the MS  101  user is not authorized to use the conference call feature/function, the NSP  106  will return the MS  101  user to the two-way call in progress state at step  5101 . Upon returning to step  5101  an announcement may be played to MS  101  user indicating that the conference call feature/function is not available and information on how to subscribe for the service. 
     After the VAP  103  is instructed by the NSP  106  to proceed with the conference call setup, the VAP  103  initiates, for example, a three-way call by first instituting a second call reference (CR=2) at step  5104  and places the first call, first call reference (CR=1), on hold. Next, at decision step  5105 , the VAP  103  determines if the third party is being alerted. If so, the VAP  103  then waits to see if the third party answers. If not, VAP  103  disconnects/releases call reference  2  in step  5209  (See FIG. 52) and awaits the MS  101  user input, by pressing for example the “send” key, to determine if the original call is retrieved (steps  5203  and  5205 ) or if the original call is also dropped (step  5204 ). If the MS  101  user presses the process initiation key again between initiating the three-way call at step  5104  and providing the third party an alert at step  5105 , the input is ignored. 
     At decision step  5106  the VAP  103  determines if the third party has been connected to the MS  101  user and has answered. If so, the MS  101  and the third party are connected by the LDS  104  with a voice path for the second call reference (CR=2) at step  5107 . If not, the VAP  103  disconnects/releases the third party (CR=2) at step  5209  and awaits MS  101  user input by, for example the MS  101  user pressing the “send” button, to attempt to retrieve the second party from hold to re-establish the original two-way call at step  5205  (See FIG. 52) or release all resources at step  5204 . If possible, the VAP  103  reconnects the MS  101  user with the second party that was placed on hold and thus re-establishes the two-way call in progress at step  5205 . If the VAP can not retrieve the second party it releases all resources at step  5204 . 
     If the MS  101  user presses the conference call initiation key, for example the “send” key, twice between steps  5105  and  5106  before the third party answers, the VAP  104  will disconnect the third party, attempt to retrieve the second party, and re-establish a two-way call in progress, as indicated at steps  5201 - 5205 . However, if the MS  101  user presses the conference call initiation key, for example the “send” key, once between step  5105  and  5106  the input will be ignored. 
     Once the MS  101  user is connected in a two-way voice path with the third party the MS  101  user may enter a code message, by pressing at any time, for example the “send” button to enter the process initiate button, as indicated at step  5108 . This will retrieve the second party and connect them to the existing voice path between the MS  101  and the third party so that a three-way call is in progress as indicated at steps  5109  and  5110 . If the MS  101  user does not enter a code message by, for example, pressing the “send” button or the second party can not be retrieved, the LDS  104  will leave the MS  101  user connected with the third party at step  5107 . Further, if the MS  101  user enters a code message by pressing, for example, the “send” button again before the three-way call is established, the input will be ignored. On the other hand, if the MS  101  user enters a different code message by, for example, pressing the conference call initiation key, e.g., the “send” key twice after the three-way call has been established, as indicated at step  5206 , the NSP  106  will instruct the VAP  103  to drop the third party as indicated in step  5207 . Next, the VAP  103  will retain the MS  101  user and the second party in a two-way call as indicated in step  5208 . If the MS  101  user enters a code message by pressing, e.g., the conference call initiation key, for example the “send” key, only once after the three-way call has been established, it will be ignored. 
     An embodiment of the conference call feature/function of the present invention illustrating an exemplary three-way call signal flow is shown in FIG. 53. A successful conference call setup procedure has in general four basic steps. These general steps are: (1) establishing a first active call between an MS  101  user and a second party (or parties); (2) placing the active call between the MS  101  user and the second party (or parties) on hold; (3) establishing a second active call between the MS  101  user and a party to be added, e.g., a third party; and (4) re-connecting the second party on hold to the second active call. A detailed discussion of the signal flow for achieving each of these steps and more specific steps of a successful conference call process follows for an exemplary embodiment using a three party conference call as an example. 
     First, the MS  101  user is a party to an active call with a party having a PSTN DN1  125   a  indicated as Call in progress (CR=1)  5301 . When the MS  101  user wants to set up a three-way conference call with another PSTN user, PSTN DN2  125   b  (whose DN is herein referred to as ThreeWayDN), the MS  101  user enters the conference call feature code, for example “*33#” and the party to be added DN digits in the format of *33#ThreeWayDN and presses, for example, the “send” button on MS  101 . The MS  101  sends to VAP  103  an IS-136 Send Burst DTMF message for each digit pressed. In the conference call procedure, the VAP  103  is responsible for receiving and buffering the digits, i.e. *33#ThreeWayDN, generated by the MS  101  in the form of IS-136 Send Burst DTMF messages. By pressing the “send” button, the MS  101  generates an IS-136 Flash With Info message which initiates packing of the previously depressed digits, so that the VAP  103  construes as one message the string of digits sequentially input earlier, i.e., the IS-136 Send Burst DTMF [*33#ThreeWayDN]  5302  message. Upon receiving each IS-136 Send Burst DTMF message from the MS  101 , the VAP  103  sends an IS-136 Send Burst DTMF ACK  5303  message to the MS  101 . 
     The IS-136 Send Burst DTMF  5302  messages include data fields such as: Protocol Discriminator, Message Type, Request number (DN), and Digit. The IS-136 Send Burst DTMF ACK  5303  message includes data fields such as Protocol Discriminator, Message Type, Request number (DN), Remaining Length, and Last Decoded Parameter. 
     The MS  101  user initiates a conference call feature/function by entering a command, for example, by pressing the “send” key on the MS  101 , which results in a IS-136 Flash with Info  5304  message being sent from the MS  101  to the VAP  103 . After receiving the Flash With Info  5304  message, the VAP  103  acknowledges receipt by sending Flash With Info Ack  5306  message to the MS  101  and requests initiation of a conference call feature/function setup procedure by sending a novel Feature Request [*33#ThreeWayDN]  5305  message including the buffered digits *33#ThreeWayDN, to the NSP  106 . 
     Upon receiving the Feature Request message from the VAP  103 , the NSP  106  searches the WCSD in, for example memory  1240 , and verifies that the MS  101  user has subscribed to the conference call feature, that the three-way call feature (assuming an LDS  104  has a three-way switch), and that the MS  101  user is not active on another three-way call initiated by him. The NSP  106  then sends a unique Feature Request ACK message, Feature Request ACK [3-Way, ThreeWayDN]  5307  message, containing the 3-Way as the action and the ThreeWayDN as the CalledDN. It also starts the T 31  timer that will wait for the 3-Way Proceeding [success]  5324  message. In the situation where the MS  101  is authorized for the conference call capability and the LDS  104  has sufficient switch capacity to add another party to the conference call, the VAP  103  will play an announcement (or tone) to the MS  101  informing the MS  101  user (and optionally all parties to the conference call) that the conference call setup has been initiated, for example, Voice Prompt (3-way call initiated)  5308 . On the other hand, if the MS  101  user who initiates the conference call is not authorized to make a three-way call, the NSP  106  sends a Feature Request ACK message with the action as Invalid 3-Way, so as to trigger an indication to the MS  101  user that the conference call feature/function is not available to them and the normal 2-way call will remain in progress. In either case, the VAP  103  may play the appropriate taped or voice synthesis generated announcement using, for example, the VPU  1235 , or alternatively generates a tone to the MS  101  user and optionally to the PSTN DN1  125   a  or the MS  101  may display a text message, as the indication of status. 
     Then the VAP  103  sends a Q.931 Info [CR=1,FA=Conf]  5309  message with the Feature Activation set to conference call to the LDS  104  to initiate a three-way conference call, updates a record to identify that this is a three-way call, and starts the T 32  timer awaiting a response from the LDS  104 . The LDS  104  acknowledges by sending a Q.931 Info [CR=1,FI=Conf,Active]  5310  message with the Feature Indication set to an active conference call and the VAP  103  cancels the T 32  time. 
     At this point, the WCS begins a procedure to place the first call between the MS  101  user and the 2nd party at PSTN DN1  125   a  on hold to allow connection between the MS  101  user and a 3rd party on another line. Once the VAP  104  gets a Q.931 Info message from the LDS  104  it cancels the T 32  timer, sends a Q.932 Hold [CR=1]  5311  message to the LDS  104  instructing the LDS  104  to place the existing call with PSTN DN1  125   a  on hold, and starts a THh timer. However, if the T 32  expires, the VAP  103  will log an error and send a 3-Way Proceeding message as fail to the NSP  106  with the cause value indicating that 3-way call could not be initiated. The NSP  106  and VAP  103  will update the call record information to indicate that the normal 2-way call is now in progress. 
     If the T 32  time does not expire, the LDS  104  puts the first leg of the call on hold, i.e., proceeds to place the voice path with PSTN DN1  125   a  on hold, and sends a Q.931 Hold Ack [CR=1]  5312  message to the VAP  103  indicating that the first active call has been placed on hold. The VAP  103  cancels timer THh and sends a Q.931 Setup [CR=2, ThreeWayDN]  5313  message to the LDS  104 , including the second call reference number (CR=2) and the ThreeWayDN, to setup the conference call to the third party [CR=2] on the same B-channel. However, if the timer THh expires, the VAP  103  will log an error and send a 3-Way Proceeding  5316  message as fail to the NSP  106  with the cause value indicating that 3-way call could not be held. The VAP  103  and NSP  106  will update the call record information to indicate that the normal 2-way call is now in progress. 
     If timer THh does not expire, the VAP  103  updates the information about this call in the appropriate record to identify that a 3-Way call is being established and starts the T 303  timer awaiting a Q.931 Call Proceeding  5316  message from the LDS  104 . Thus, the first referenced call (CR=1) is now held by the LDS  104  awaiting the connection of MS  101  with other parties (Call Held by LDS (CR=1)  5315 . The NSP  106  updates the information about this call in the appropriate record in the WCSD of, for example, in the memory  1240 . 
     When the first call between the MS  101  user and the second party, PSTN DN1  125   a  has been put on hold the WCS then continues with the conference call setup procedure by performing a call setup between the MS  101  and a party to be added to the conference call, for example, a third party at PSTN DN2  125   b.  First, the LDS  104  processes the Q.931 Setup [CR=2, ThreeWayDN]  5313  message and sends a Q.931 Call Proceeding  5316  message to the VAP  103  indicating to the VAP  103  that the call to PSTN DN1  125   b  is being initiated. Once the VAP  103  receives a Q.931 Call Proceeding  5316  message from the LDS  104 , it cancels the T 303  timer and starts T 310  timer waiting for Q.931 Alerting  5319  message from the LDS  104 . The VAP  103  does not have to do anything on the RF side because the MS  101  is already on the DTC. However, if the timer T 303  expires, the VAP  103  will send a novel 3-Way Proceeding  5324  message as “fail” to the NSP  106  with a proper cause value. It will also send a Q.931 Release Complete [CR=2]  5330  message to the LDS  104 . After this the VAP  103  will start a timer T 34  waiting for a Flash with Info message from the MS  101  (this would indicate that the mobile wants to retrieve the original call). 
     Next, the LDS  104  sends an initial address message, ISUP IAM  5317 , to the ThreeWayDN, in this example another PSTN LDS, PSTN DN2  125   b.  In response, the PSTN DN2  125   b  sends an address complete message, ISUP ACM  5318 , to indicate that a communication link has been made with PSTN DN2  125   b.  Next, the LDS  104  sends a Q.931 Alerting  5319  message to the VAP  103  so that the VAP  103  and LDS  104  can provide MS  101  Ringback Tone  5320  indicating that PSTN DN2  125   b  is being alerted of an incoming call. When the VAP  103  receives a Q.931 Alerting  5319  message from the LDS  104 , it cancels the timer T 310  and starts T 301  timer waiting for Q.931 Connect  5322  message from the LDS  104 . However, if the timer T 310  expires, the VAP  103  will follow disconnect procedure by sending Q.931 Disconnect (CR=2) message to the LDS  104 . The LDS  104  will respond with Release (CR=2)  5329  message. The VAP  103  will continue to follow the same procedure as above; the VAP  103  will also send a Q.931 Release Complete [CR=2]  5330  message to the LDS  104 . After this the VAP  103  will start a timer T 34  waiting for a Flash with Info message from the MS  101  (this would indicate that the mobile wants to retrieve the original call). 
     When the third party at PSTN DN2  125   b  answers the call an answer message, ISUP ANM  5321 , is sent from PSTN DN2  125   b  to LDS  104 . In response, the LDS  104  sends a Q.931 Connect  5322  message to the VAP  103 . When the VAP  103  gets the Q.931 Connect  5322  message from the LDS  104 , it recognizes that this message corresponds to a three-way call and cancels the T 301  timer. If the timer T 310  expires, the VAP  103  will follow disconnect procedure by sending Q.931 Disconnect (CR=2) message to the LDS  104 . The LDS  104  will respond with Release (CR=2)  5329  message. The VAP  103  will continue to follow the same procedure as above; the VAP  103  will also send a Q.931 Release Complete [CR=2]  5330  message to the LDS  104 . After this the VAP  103  will start a timer T 34  waiting for a Flash with Info message from the MS  101 . Otherwise, the VAP  103  then sends a Q.931 Connect ACK  5323  message to the LDS  104  acknowledging the second call connection has been made between the MS  101  and PSTN DN2  125   b  and starts a T 34  timer. (The voice path of the second call is illustrated in FIG. 53 as dashed arrow lines labeled Call in progress (CR=2)  5414  from the PSTN DN2  125   b  to MS  101 .) 
     Once the voice path has been established the VAP  103  sends a novel 3-Way Proceeding [success]  5324  message to the NSP  106  indicating that the third party has been successfully added to the conference call by completing the second call between MS  101  and PSTN DN2  125   b.  This message includes the MSID, the Call Reference Number (CR=2), and the Cause (Success/Fail) fields. (The cause field in the 3-Way Proceeding message may contain the comments, for example: 3rd party answered (success), 3-way call hold fail, 3-way call initiate fail, or 3rd party did not answer.) At this point, establishing a second call between the party to be added, in this case a third party, has been completed and thus the MS  101  for the conference call setup procedure is complete with the exception of a few administrative details to be performed by the NSP  106 . 
     When the NSP  106  gets a 3-Way Proceeding [success]  5324  message it updates the information about this call in the appropriate record in the WCSD to, among other things, capture the call usage time for the new leg of the call. The NSP  106  cancels the T 31  timer, updates the call record information and starts the T 36  timer that waits for the 3-way Result [success]  5433  message from the VAP  103  indicating that the conference call setup has been completed successfully. However, if the second call to the third party is not connected for whatever reason, for example, the T 31  timer expires and/or the NSP  106  receives 3rd Party Answered message as a “fail”, the NSP  106  will send a 3-Way Disconnect message to the VAP  103  to disconnect the attempted connection with the third party, retrieve the original call with PSTN DN1 which was placed on hold (as discussed in more detail below), and update the call information record to indicate that a normal 2-way call is now in progress. 
     If the MS  101  user had requested to set up a conference call by adding another MS  101  rather than the PSTN DN2  125   b,  the call setup procedure would have followed the sequence described in other areas of the invention for call setup from one MS  101  to another MS  101  in the WCS. 
     Next, the conference call setup procedure connects the original call with the second party at PSTN DN1  125   a  on hold with the active call between MS  101  and the third party at PSTN DN2  125   b.  If the MS  101  user once again inputs the initiation code, for example by pressing the “send” button once, an IS-136 Flash with Info  5325  message is sent to the VAP  103  requesting that the second party on hold be added to the two-way call between the MS  101  user and the third party. The VAP  103  cancels the T 34  timer, sends a Q.932 Retrieve [CR=1]  5326  message to the LDS  104  indicating that the MS  101  user has requested that the call on hold be retrieve so that it and the active call be combined to form, in this case, a three way conference call, starts the TRr timer, and sends an IS-136 Flash with Info Ack  5327  message to the MS  101 . However, if the timer T 34  expires, the VAP  103  will follow the Release procedure to release CR=1and send 3-Way Result as fail to the NSP  106 . A 2-Way call with third party would continue. 
     When the LDS  104  receives the Q.932 Retrieve [CR=1]  5326  message from the VAP  103  (after the third party has answered), it verifies that the original called party, in this case the second party, is still present on hold, and sends a Retrieve Ack  5328  message to the VAP  103  indicating that the original call on hold has been retrieved. The LDS  104  then mergers the calls, CR=2 with CR=1. When the VAP  103  receives Q.932 Retrieve Ack [CR=1] message from the LDS  106 , it will stop the TRr timer and start T 35  timer. However, if the timer TRr expires as a result of the VAP  103  not receiving the Q.932 Retrieve Ack  5327  message because, for example, the second party hangs up or is some way disconnected, the VAP  103  will log an error and send a 3-way Result message as fail to the NSP  106  and the 2-way call [CR=2] with the third party will continue. In the case of such a failure to retrieve the first call placed on hold, the VAP  103  may also play a voice prompt to the MS  101  user indicating that the 3-way call could not be completed. 
     After merging the two legs of the call, CR=1 and CR=2, the LDS  104  sends a Q.931 Release [CR=2]  5329  message to the VAP  103  to release the second call reference (CR=2) while retaining the three (or more) parties on the conference call. Then VAP  103  cancels timer T 35  and releases (clears) the second call reference CR=2 and sends a Q.931 Release Complete [CR=2]  5330  to the LDS  104 . However, if the timer T 35  expires, the VAP  103  will log an error. The 3-way call is in progress so the VAP  103  will send a Q.931 Release [CR=2]  5329  message to the LDS  104  to release the second call reference. Once the VAP  103  gets a Q.931 Release Complete [CR=2]  5330  message from the LDS, it will send a 3-way Result [success]  5331  message to the NSP  106 . 
     In any case, the VAP  103  sends a novel 3-Way Result [success]  5331  message to the NSP  106  indicating that the release of CR=2 is successful. The 3-Way Result message includes MSID, Call Reference Number, and Cause fields. Then the NSP  106  cancels the timer T 36  and updates the call record information to indicate successful setup of a conference call, in this case a three-way call, and that the conference call is now in progress (indicated as the dashed arrows labeled (3-Way Call In-Progress (CR=1)  5332 ). 
     However, if the NSP  106  receives a 3-Way Result message from the VAP  103  indicating a “fail”, the NSP  106  will cancel the T 36  timer and update the call record information to indicate that the normal 2-way call [CR=2] is in progress. If the T 36  timer expires, the NSP  106  will initiate a Release procedure on CR=2. In either case, the NSP  106  may send a Play Voice Prompt message to the VAP  103  to inform the user that the conference call could not be completed and a two-way call will continue. Further, if any party disconnects during the establishment of a three-way call, the NSP  106  will get a WCS specific Release message. Then the NSP  106  will update its call record information and resource table accordingly. 
     In some circumstances, although the third party may answer, the equipment may fail to be able to connect the third party to the original call. In such a case, the WCS will need to notify the MS  101  user and the MS  101  user may wish to retrieve the original call. FIG. 54 below gives the signal flow for one exemplary embodiment when the third party could not be connected. 
     The signal flow in the case where the third party could not be connected to the conference call is essentially the same as described for FIG. 53 up to the point where the VAP  103  sends 3-Way Proceeding [success]  5324  message. In general, the original call, call reference  1 , is placed on hold by the LDS, Call Held by LDS(CR=1)  5315  message. Subsequently, the third party line PSTN DN2  125   b  sends an ISUP ACM  5318  message to the LDS  104 . In response the LDS provides a Q.931 Alerting  5319  message to the VAP  103  and a Ringback Tone  5320  to the MS  101 . However, in the case where the third party could not be connected to the conference call, the 3-Way Proceeding message from the VAP  103  results in a “fail” message being sent to the NSP  106 , i.e., 3-Way Proceeding [fail]  5452 . 
     After sending 3-Way Proceeding [fail]  5452  message, the VAP will start a timer T 34  waiting for Flash with Info message from the mobile and provide an indication to the MS  101  user that the third party can not be connected. For example, the MS  101  use may receive a Voice Prompt: Can not connect 3rd Party  5453  or a similar text message, which prompts the MS  101  user to respond accordingly. If the MS  101  user enters the initiation code, for example, by pressing the “send” key, the VAP  103  will be sent a IS-136 Flash with Info  5454  message from the MS  101 . The VAP  103  will cancel timer T 34 , send a Q.931 Retrieve [CR=1]  5455  message to the LDS  104  to re-connect with the original call, send and IS-136 Flash with Info Ack [CR=1]  5456  message to the MS  101 , and start timer TRr. However, if the timer T 34  expires, the VAP  103  will follow a disconnect procedure and send a WCS Release message to the NSP  106  so that all calls are disconnected and all resources released. If the time T 34  does not expire, the LDS responds with Q.931 Retrieve ACK [CR=1]  5457  message and the VAP  103  will cancel the TRr timer and update its call record to reflect that the original call has been received and the conference call latest attempt to add a party has been cancelled. The WCS will establish the original call, for example, 2-Way Call in Progress(CR=1)  5458 . On the other hand, if the timer TRr expires, the VAP  103  will release RF resources, clear the call reference on its side, send a Q.931 Release [CR=1] message to the LDS  104 . Once the VAP  103  receives Q.931 Release Complete message from the LDS  104 , it will send a WCS Release message to the NSP  106  with a proper cause value. 
     In some instances the MS  101  user may wish to retrieve the original call with the 2nd party before a conference call, e.g., a three way call, is established. FIG. 55 depicts the signal flow for the scenario when the MS  101  user wants to retrieve the original call with the second party before the third party answers. To do so, the MS  101  user can enter the feature initiation code twice, for example, he may press the “send” button twice in certain scenarios. In particular, if the original call with the second party is on hold and the third party has not yet answered the incoming call, the conference call setup procedure can be easily cancelled by, for example, the MS  101  user entering the feature initiation code twice within a short period of time, e.g., pressing the “send” button twice within for example, approximately one-two seconds. Upon canceling the conference call the ongoing connection to the party to be added, e.g., the third party, will be disconnected and the party(ies) of the original call, e.g., the second party, will be retrieved. A detailed discussion of the signal flow for retrieving an original call on hold before a conference call is established follows, using a three-way conference call as an example. 
     Assuming that the conference call has been initiated and the third party is being alerted, in essence, the conference call setup procedure has progressed successfully in the normal manner to the point where the original call to the second party is on hold (signals Call Held by LDS (CR=1)  5315 , and Q.931 Call Proceeding  5316  already complete) and the party to be added to the conference call is being alerted of an incoming call (ISUP IAM  5317  already complete), if the MS  101  user enters a feature initiation code twice within a short period of time, e.g., within a 1 to 2 seconds, e.g., presses the “send” button twice, the MS  101  will send the VAP  103  two IS-136 Flash With Info  5502  and  5504  messages sequentially. In response, VAP  103  send two IS-136 Flash with Info ACK  5503  and  5505  messages sequentially to the MS  101 . 
     When the VAP  103  gets the first IS-136 Flash with Info  5502  message from the mobile, the VAP  103  checks the call information record to determines that this is a three-way call, that the third party has not answered, that the original call with the second party is in a held state, and starts the T 37  timer, awaiting another IS-136 Flash with Info message, IS-136 Flash with Info  5504  message. If the timer T 37  expires, the VAP  103  will ignore the first Flash with Info message. Otherwise, the VAP  103  gets the second IS-136 Flash with Info message, IS-136 Flash with Info  5504  message from the MS  101 , cancels the T 37  timer, and sends an IS-136 Flash with Info Ack  5505  message to the MS  101 . The VAP  103  also determines that this is a request to disconnect the ongoing conference call connection and retrieve the original call. So the VAP  103  then sends a Q.931 Disconnect [CR=2]  5506  message to the LDS  104  and starts a T 305  timer. 
     The VAP  103  sends a Q.931 Disconnect [CR=2]  5506  message to the LDS  104  instructing it to disconnect the call setup to the party to be added, e.g., the third party. The LDS  104  then sends release messages, ISUP REL  5507  message to PSTN DN2  125   b  and Q.931 Release [CR=2]  5508  message to the VAP  103 , to terminate the call setup in mid-process. PSTN DN2  125   b  responds by releasing the call setup and sending a confirmation to the LDS  104 , the ISUP RLC  5509  message. Once the VAP  103  gets a Q.931 Release [CR=2]  5508  message from the LDS  104 , it cancels the T 305  timer, sends a Q.931 Release Complete[CR=2]  5510  message to the LDS  104  followed by Q.932 Retrieve [CR=1]  5511  message to the LDS  104  and waits for Q.932 Retrieve Ack  5513  message from the LDS  104 . However, if the T 305  timer expires, the VAP  103  logs an error, releases CR=2 at its end, sends a Q.931 Release Complete  5510  message to the LDS  104  and continues. 
     When the call to the party to be added is released, the VAP  103  proceeds to retrieve the original call to the second party from hold and reconnect the call between the MS  101  user and the second party on the PSTN DN1  125   a.  To do so, the VAP  103  sends the Q.932 Retrieve [CR=1]  5511  message to the LDS  104  so that the LDS will retrieve the call on hold and starts the TRr timer. The LDS  104  responds to the VAP  103  with a Q.932 Retrieve Ack  5513  message and re-establishes the original call between the original parties to the conference call, e.g., the second party and the MS  101  user as illustrated by the dotted line with arrows labeled 2-Way Call in Progress(CR=1)  5512 . However, if the timer TRr expires and the VAP  103  does not get Q.932 Retrieve Ack.  5513  message from the LDS  104 , it will release all the resources. The VAP  103  will also clear the call reference (CR=1) on its side and send a Q.931 Release message to the LDS  104 . Once the VAP  103  gets Q.931 Release ACK message from LDS  104 , it will then send a WCS Release message to the NSP  106  with a proper cause value (2 nd  party could not be retrieved) and the air interface usage for the call. 
     When the VAP  103  gets the Q.931 Retrieve Ack  5513  message from the LDS  104 , it sends a novel 3-Way Release [3rd Party not Answered]  5514  message to the NSP  106 . This novel WCS 3-Way Release message includes fields for MSID, Call Reference Number, and Cause (3rd Party not Answered/3rd party dropped). When the NSP  106  receives 3-Way Release [3 rd  party not answered]  5514  message from the VAP  103 , it updates it call record information in the WCSD to say that only 2-way call is now in progress. If the NSP  106  receives a WCS Release message from the VAP  103 , the NSP  106  will update its call record to capture call usage information. 
     B. Deleting A Party From An Existing Call 
     The WCS provides the feature/function to allow an MS  101  user to delete (drop) a party from an active conference call. Once a conference call has been established, an MS  101  user may enter delete a party feature/function code in the MS  101  which will trigger a party to be dropped from the conference call. 
     For ease of explanation and convenience, an exemplary embodiment is provided below for a situation in which an MS  101  user drops the last added party from a three way conference call between an MS  101  user and two parties using PSTN telephones. However, one skilled in the art would recognize that the present invention also similarly covers scenarios where the conference call includes more than three people and the MS  101  user desires to delete (drop) a party other than the last added party. In such a case the delete a party feature/function message may also include, for example, a deactivation code and a directory number indicating the party to be deleted. 
     Referring now to FIG. 56, a preferred embodiment is illustrated having signal flow for a situation when an MS  101  user drops the last added party from a three party conference call initiated by the MS  101  user, i.e., deleting (dropping) the third party during and active three-way call. In this case, the MS user enters a delete last party message, for example entering a conference call feature/function message by pressing the “send” button twice, to thereby drop the last added call during a three-way call. 
     While a three-way call is in progress, 3-Way Call In-Progress (CR=1)  5601 , the MS  101  user decides to delete (drop) the last party added, PSTN DN2  125   b,  from the active conference call. To achieve this, the MS  101  user may, for example, enter the conference call feature/function message by pressing the “send” button twice within a certain period of time (e.g., a few seconds). This sequence will indicate to the VAP  103  that the MS  101  user wishes to delete (drop) a party from a conference call, e.g., PSTN DN2  125   b.    
     In one example, the VAP  103  receives the first of two feature/function initiation codes, IS-136 Flash with Info  5602  message, from, the MS  101 . The VAP  103  checks the call information record to determine that a three-way active conference call is in progress. The VAP  103  starts a T 37  timer awaiting another IS-136 Flash With Info message and sends an IS-136 Flash With Info Ack  5603  message back to the MS  101 , indicating receipt of the earlier sent IS-136 Flash With Info  5602  message. If the VAP  103  gets another IS-136 Flash With Info message before the T 37  timer times out (e.g., within a few seconds), IS-136 Flash With Info  5604  message from the MS  101 , the VAP  103  determines that this is a request to drop the last added party. In another embodiment the Flash With Info Message could be proceeded by the conference call feature function deactivation code and the DN to be dropped. This process would include a query of the NSP  106  for instructions as to which line to drop. In any case, if the timer T 37  expires, the VAP will ignore the first Flash with Info message. 
     Assuming the MS  101  has entered two Flash With Info messages before the T 37  timer times out, the VAP  103  determines that a three-way call is in progress and that this is a request to drop the last added party. Thus, the VAP  103  sends a Q.931 Info [CR=1, Drop]  5606  message to the LDS  104  requesting it to disconnect, for example, the last added party of the three-way call (CR=1). 
     The LDS  104  then initiates the Release process with PSTN DN2  125   b  by sending an ISUP REL  5607  message to the PSTN DN2  125   b.  After sending a Q.931 Info [CR=1, Drop] message to the LDS  104 , the VAP  103  sends a 3-Way Release [3rd party dropped]  5610  message with cause value as 3 rd  party dropped to the NSP  106 . The LDS  104  may send back a Q.931 Info [CR=1, Conf. Display Info]  5609  message to the VAP  103  informing the VAP  103  that the last added call has been dropped. However, the VAP  103  does not have to wait for the Q.931 Info [CR=1, Conf Display Info]  5609  message and will ignore it when it gets this message if the VAP  103  has already sent the 3-Way Release [3rd party dropped]  5610  message. In any case, the VAP  103  will send a 3-Way Release [3rd party dropped]  5610  message to the NSP  106  and releases the last added party to the conference call. When the NSP  106  receives 3-Way Release message from the VAP  103 , it will update the call record information to say that 2-Way call is now in progress, 2-Way Call In Progress  5611 , between PSTN DN1  125   a  and MS  101 . 
     In another embodiment the VAP  103  may play an announcement to one or more party (ies) of the conference call indicating that a party is being dropped from the active conference call. 
     Although particular embodiments of the present invention have been shown and described, it will be understood that it is not intended to limit the invention to the preferred embodiments and it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention. Thus, the invention is intended to cover alternatives, modifications, and equivalents, which may be included within the spirit and scope of the invention as defined by the claims. 
     For example, while the IS-136 standard is used to illustrate the invention in various embodiments described herein, the invention is rot limited to use in the IS-136 standard. The invention is also applicable to other cellular and/or PCS systems. Furthermore, while the access methodology employed by the various embodiments of the instant invention involves the use of a Time Division Multiplexing Access (TDMA) scheme, the general concepts disclosed herein are not limited to the TDMA IS-136 standard. The concepts are applicable to other access methodologies such as, Frequency Division Multiple Access (FDMA), Code Division Multiple Access (CDMA), or other multiple access techniques. As a result, the use of TDMA IS-136 standard is used to enable the invention and is in no way intended to be a limitation of the invention. 
     The following applications are hereby incorporated by reference for all purposes: 
     1. U.S. patent application Ser. No. 09/223,316 by Chow et al. filed on Dec. 30, 1998 entitled Neighborhood Cordless Service Call Handoff; 
     2. U.S. patent application Ser. No. 09/223,321 by Chow et al. filed on Dec. 30, 1998 entitled Automatic Service Selection Feature for Neighborhood Cordless Service; 
     3. U.S. patent application Ser. No. 09/223,317 by Chow et al. filed on Dec. 30, 1998 entitled Method and Apparatus for Billing a Neighborhood Cordless Service; 
     4. U.S. patent application Ser. No. 09/223,318 by Chow et al. filed on Dec. 30, 1998 entitled Method and Apparatus for Over-the-Air Activation of Neighborhood Cordless Service; 
     5. U.S. patent application Ser. No. 09/223,322 by Chow et al. filed on Dec. 30, 1998 entitled Method and Apparatus for Providing Neighborhood Residential Cordless Service; 
     6. U.S. patent application Ser. No. 09/223,320 by Chow et al. filed on Dec. 30, 1998 entitled Automatic Status Indicators For Neighborhood Cordless Service; and 
     7. U.S. patent application Ser. No. 09/224,724 by Chow et al. filed on Dec. 31, 1998 entitled Instantaneous Conference Initiation. 
     The following applications, which have each been filed on the same day as the present application, are incorporated by reference as to their entire contents for all purposes: 
     1. U.S. patent application Ser. No. 09/460,456, filed Dec. 13, 1999, (Client Reference No. 113421-CIP-13), entitled “Wireless Centrex Conference Call Adding A Party,” invented by Chow et al. 
     2. U.S. patent application Ser. No. 09/460,385, filed Dec. 13, 1999, (Client Reference No. 113421-CIP-4), entitled “Wireless Centrex Conference Call Deleting A Party,” invented by Chow et al. 
     3. U.S. patent application Ser. No. 09/460,116, filed Dec. 13, 1999, (Client Reference No. 113421-CIP-5), entitled “Wireless Centrex Automatic Callback,” invented by Chow et al. 
     4. U.S. patent application Ser. No. 09/458,831, filed Dec. 13, 1999, (Client Reference No. 113421-CIP-3), entitled “Unconditional Call Forwarding In A Wireless Centrex Services System,” invented by Chow et al. 
     5. U.S. patent application Ser. No. 09/458,842, filed Dec. 13, 1999, (Client Reference No. 113421-CIP-2), entitled “Programmable Ring-Call Forwarding In A Wireless Centrex Services System,” invented by Chow et al. 
     6. U.S. patent application Ser. No. 09/460,246, filed Dec. 13, 1999, (Client Reference No. 113421-CIP-1), entitled “Time-of-Day Call Forwarding In A Wireless Centrex Services System,” invented by Chow et al. 
     7. U.S. patent application Ser. No. 09/460,383, filed Dec. 13, 1999, (Client Reference No. 113421-CIP-12), entitled “Wireless Centrex Call Screen,” invented by Chow et al. 
     8. U.S. patent application Ser. No. 09/459,470, filed Dec. 13, 1999, (Client Reference No. 113421-CIP-7), entitled “Wireless Centrex Call Transfer,” invented by Chow et al. 
     9. U.S. patent application Ser. No. 09/458,823, filed Dec. 13, 1999, (Client Reference No. 113421-CIP-14), entitled “Call Waiting In A Wireless Centrex System,” invented by Chow et al. 
     10. U.S. patent application Ser. No. 09/458,840, filed Dec. 13, 1999, (Client Reference No. 113421-CIP-8), entitled “Wireless Centrex Caller ID,” invented by Chow et al. 
     11. U.S. patent application Ser. No. 09/460,386, filed Dec. 13, 1999, (Client Reference No. 113421-CIP-9), entitled “Distinctive Ringing In A Wireless Centrex System,” invented by Chow et al. 
     12. U.S. patent application Ser. No. 09/458,737, filed Dec. 13, 1999, (Client Reference No. 113421-CIP-10), entitled “Speed Calling In A Wireless Centrex System,” invented by Chow et al. 
     13. U.S. patent application Ser. No. 09/459,541, filed Dec. 13, 1999, (Client Reference No. 113421-CIP-11), entitled “Busy Call Forwarding In A Wireless Centrex Services System,” invented by Chow et al. 
     14. U.S. patent application Ser. No. 09/460,151, filed Dec. 13, 1999, (Client Reference No. 113559-CIP), entitled “Wireless Centrex Call Hold,” invented by Chow et al. 
     15. U.S. patent application Ser. No. 09/460,392, filed Dec. 13, 1999, (Client Reference No. 113421-CIP-15), entitled “Wireless Centrex Feature Activation/Deactivation,” invented by Chow et al. 
     16. U.S. patent application Ser. No. 09/460,391, filed Dec. 13, 1999, (Client Reference No. 113481-CIP), entitled “User Proactive Call Handling,” invented by Brachman et al. 
     17. U.S. patent application Ser. No. 09/459,324, filed Dec. 13, 1999, (Client Reference No. 113421-CIP), entitled “Wireless Centrex Services,” invented by Chow et al.