PATENT ABSTRACT
A locator system has a plurality of locator transmitters, each transmitter transmitting a unique locator signal. Paging devices are carried by each user of the locator system and each paging device includes: (i) a receiver responsive to signals broadcast from the locator transmitters, (ii) a unique identification code stored therein, and (iii) a signal transmitter and controller for controlling the signal transmitter, the controller causing the transmitter to transmit location and identification signals based upon the locator signal received by the receiver and the unique identification code. A receiver is responsive to the signals transmitted by the signal transmitters in the paging devices and a control system handles communications from other parties to the users. The control system is coupled with the receiver and responsive to received location and identification signals to determine where to direct communications from other parties intended for a user.

PATENT DESCRIPTION
INCORPORATION BY REFERENCE 
     This application is a division of application Ser. No. 08/447,751 filed May 23, 1995, now U.S. Pat. No. 6,026,153, which application is in turn a division of Ser. No. 08/249,453 filed May 26, 1994, which application is in turn a division of application Ser. No. 07/480,242, filed Feb. 15, 1990 (now U.S. Pat. No. 5,375,161, issued Dec. 20, 1994), which is a continuation-in-part of application Ser. No. 07/439,601, filed Nov. 21, 1989 (now abandoned), which is a continuation-in-part of application Ser. No. 06/841,931, filed Mar. 20, 1986 (now U.S. Pat. No. 4,893,335, issued Jan. 9,1990), which is a continuation-in-part of application Ser. No. 06/650,821, filed Sep. 14, 1984 (now abandoned). 
     The subject matter disclosed and claimed in copending and allowed U.S. Application Ser. No. 06/841,931, entitled “Remote Access Telephone Control System”, invented by the same inventors and assigned to the same assignee as the instant application, is hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention pertains to the telephone equipment art and, more particularly, to a telephone control system which allows subscribers to remotely control a plurality of call handling utilities to predeterminedly direct incoming calls. 
     Despite the availability of numerous telephone central exchange provided functions, such as “call-forwarding”, “three-way calling”, “call-waiting” and “speed-dialing”, as well as the advent and availability of paging and mobile telephone systems, the completion of a call to a system subscriber can often be a complicated, time consuming and tedious task. Unless the telephone subscriber is located at the telephone which receives calls to his assigned phone number, completion of a call from a calling party, despite the aforementioned services, generally involves the calling party leaving a message and awaiting a call back by the subscriber. Even if the subscriber is accessible via mobile telephone or a paging system, human intervention is commonly required to look up and dial specific mobile telephone or paging numbers to attempt to contact the subscriber. Thus, additional delays and costs are incurred. 
     In addition, even if the subscriber is on a paging system, the successful direction of a message to the subscriber requires that the subscriber manually inform the system of his whereabouts. 
     Finally, existing telephone control systems offer very limited control to either the subscriber or the calling party with respect to the processing of calls. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention, therefore, to provide a telephone control system which allows subscribers to access the system, even remotely, and implement any of a number of utilities for the handling of subscriber directed calls. 
     It is a further object of the invention to provide a telephone control system wherein each subscriber is assigned one telephone number and calls to the system on that number are automatically directed to the subscriber regardless of his location. 
     It is a further object of the invention to provide the above described telephone control system wherein the system interfaces with callers and subscribers via courtesy messages which minimize or eliminate the need for users to recall complicated control commands. 
     It is a further object of the invention to provide the above described control system wherein subscribers are provided with portable pager-like communicators which include RF transmitters for transmission directly to the paging system. 
     It is a further object of the present invention to provide the above described control system wherein the communicator devices automatically respond to remote locater transmitters to transmit back to the control system the phone number of a telephone proximate the user. 
     These and other objects of the invention will be more fully understood with reference to the detailed description and claims herein below. 
     In summary, the present invention is directed to a control system which is connected to a telephone exchange and wherein each user of the system is assigned a unique telephone number with the control system routing calls to the used via a user controlled number. The control system comprises an input/output device which is adapted for connection to the telephone exchange trunks or lines to input and output telephone calls. A switching control means controllably connects a call on one line to a different line. Provided memory controllably stores and recalls electronic signals. An electronic processing means is provided for accessing the memory, switching control means and input/output device to direct the flow of input and output calls. The electronic processing means includes means for: a) identifying a call to the system from a caller directed to a specific user, b) recalling from the memory a forwarding number for the user, c) implementing a call to the forwarding number, d) switching the caller&#39;s call to the forwarding number, e) identifying a call to the system from a specific user, f) changing the specific user&#39;s memory stored forwarding number responsive to a command from the specific user, g) processing calls to the system directed to a specific user in a selected one of a plurality of modes and, h) changing a users call processing mode responsive to a command from the user. 
     In accordance with one feature of the invention, the control system may forward incoming calls for a subscriber to a telephone number that has been preselected by the subscriber. The call may be directly forwarded, or may be preceded by a brief announcement informing the caller that the call is being forwarded. 
     In accordance with another feature of the invention, the control system may first screen incoming calls before causing them to be forwarded. The call may be screened by any of several methods, including a ‘priority-screen’ which allows the caller to determine whether or not the call should be forwarded to the subscriber, a ‘VIP code-screen’ which will only forward calls if the caller enters a preselected code, and a ‘voice-screen’ which records the caller&#39;s name and business, places the caller on hold while contacting the subscriber, plays the recorded message, and allows the subscriber to determine if he wishes to be connected to the caller. With any of these screening methods, should the call not ultimately be forwarded to the subscriber, then the call may be delivered to a ‘message center’, where a message may be left for later pickup by the subscriber. 
     In accordance with another feature of the invention, the control system may cause the subscriber&#39;s pager to be activated in conjunction with forwarding of a call. In this way, the subscriber is given notice that the call is being forwarded to the pre-selected telephone number. 
     In accordance with another feature of the invention, the control system may, prior to forwarding a call, provide a courtesy message to the caller such as “. . . when the call is answered, please ask for your party by name . . . ”, or alternately inform the caller “. . . when the call is answered, please ask for extension number 1234.” 
     In accordance with another feature of the invention, the control system may send all calls to a ‘message center’ where all messages may be left for later pickup by the subscriber. In this way the call is handled without disturbing the subscriber. 
     In accordance with another feature of the invention, the control system may handle calls via a ‘branch-routing’ mode. 
     In this mode, callers may choose from a directory of options. As an example, the caller may be told: “You have reached ABC Real Estate. Please touch 1 to speak to Mr. Smith, 2 to speak to Mr. Jones, or hold the line to speak to the receptionist.” Depending on the programming of the system, each of these selections may cause the call to be forwarded to a specific telephone number, or to another access number. No command may cause the system to follow a predetermined default method for disposing of the call. 
     In accordance with another feature of the invention, the control system may handle calls via a ‘meet-me’ mode. In this mode, the caller is placed on hold after being told that the user is being paged to a phone. The control system then pages the user. The user then may call the access system, and enter a code to be connected to the caller. In addition, the caller may be given the opportunity to touch 9 to leave a message if he does not wish to wait. If the caller chooses to leave a message, then when the subscriber calls in, he will be informed that the caller did not wait and instead left a message. If the caller hangs up without leaving a message, then the subscriber will be so informed. 
     In accordance with another feature of the invention, the call-handling modes and other features of the control system may be programmed by the subscriber by accessing a command mode by dialing the access number from a touch-tone phone, entering a Personal Identification Number (PIN) code, and then following a series of menu items to select the desired feature, call-handling mode, or forwarding number. This process is further simplified by providing the subscriber with ‘mode memories’ which contain the most often used call handling modes, and ‘number memories’ which contain often used telephone numbers such as home phone, office phone, car phone, and so on. 
     In accordance with another feature of the invention, the subscriber may invoke a ‘feature timer’ which will cause a new call handling mode to take effect at the expiration of a selected time interval. 
     In accordance with another feature of the invention, the subscriber may invoke a ‘weekly schedule’ which will cause the current call-handling mode to be automatically selected from a pre-programmed list of call-handling modes, based upon the time-of-day and day-of-week. 
     In accordance with another feature of the invention, the subscriber may cause his calls to be forwarded to him at his current location, without the subscriber needing to enter the telephone number of the current location. Instead, the telephone number of the location is automatically received by the control system as an Automatic Number Identification (ANI) via ANI-capable facilities from the Public Switched 
     Telephone Network (PSTN). The subscriber need only call the control system, enter his PIN code, and select a forwarding mode. 
     In accordance with another feature of the invention, the subscriber may program the operation of the control system by picking up a preregistered phone such as his office or home telephone and touching a 2 or 3 digit speed-dial code. In combination with the ANI capability described above this makes programming very simple. By way of example, if a subscriber is at home, he may pick up the phone and dial 10#. This causes the telephone company central office to memory dial an 800 number with an NNX that points to ANI-capable trunks connected to the control system. The control system recognizes the ANI as belonging to the home phone of one of it&#39;s subscribers. The control system then causes all calls to that subscriber to be priority-screen forwarded to the home. If the subscriber had dialed 11#, an 800 number with the same NNX but different last four digits would be dialed, which would cause the control system to select voice-screened forwarding to the home, and so forth. 
     In accordance with another feature of the invention, the subscriber may elect to make an ‘outside call’ while in the control system command mode, by touching 9 and dialing the desired telephone number. 
     The control system is further enhanced by the addition of a communicator feature. This feature allows a subscriber to move from place to place and have his calls follow him without the need for him to call into the control system. The communicator is a portable device carried on the subscriber&#39;s person. The device contains an RF transmitter, an RF receiver, an ultrasonic receiver, a keypad, a ‘beeper’, and control circuitry. The communicator receives ultrasonic messages from small wall mounted ultrasonic transmitters. These transmitters contain the phone number, and optionally the extension number, of the nearest telephone or a mode appropriate for the location such as do not disturb in a hospital operating room. The communicator also receives radio frequency messages from the control system indicating, or paging, an incoming call for the user. The communicator device can send various radio frequency messages back to the control system, including a message containing the phone number received from the ultrasonic transmitter, a message acknowledging receipt of the page, and messages in response to keypad selections by the subscriber indicating a desire to select a new mode of call handling. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram illustrating the various modes of operation and interfacing equipment for the preferred embodiment of the telephone control system; 
     FIG. 2 is a block diagram illustrating the principle components of the telephone control system; 
     FIG. 3 is a block diagram of the Communicator; 
     FIG. 4 is a block diagram of the Ultrasonic Transmitter; 
     FIG. 5 is a block diagram of the Call Processing facility; 
     FIG. 6 is a flowchart illustrating operation of the E &amp; M Control Circuit; 
     FIG. 7 is a diagram illustrating the Subscriber Master Record; 
     FIG. 8 is a diagram illustrating the Mode Memory; 
     FIG. 9 is a flowchart of the Main Task for the Call Processing facility; 
     FIG. 10 is flowchart of the Code Processing Facility—Network Message Task; 
     FIG. 11 is a flowchart of the Code Processing Facility—Call Termination Task; 
     FIGS. 12 a  and  12   b  form a flowchart of the Call Processing Facility—Call Handler Task; 
     FIG. 13 is a flowchart of the Call Processing Facility—Dynamic Mode Assignment; 
     FIGS. 14 and 14 a  form a flowchart of the Call Processing Facility—Direct Forwarding Function; 
     FIGS. 15 a  and  15   b  form a flowchart of the Call Processing Facility—Announced Forwarding Function; 
     FIG. 16 is a flowchart of the Call Processing Facility—Priority/Urgent Screen Function; 
     FIG. 17 is a flowchart of the Call Processing Facility—VIP Code screen Function; 
     FIG. 18 is a flowchart of the Call Processing Facility—Branch Routing Function; 
     FIG. 19 is a flowchart of the Call Processing Facility—Caller Message Center Function; 
     FIGS. 20 a ,  20   a - 1 ,  20   b  and  20   c  form a flowchart of the Call Processing Facility—Voice-Screen Function; 
     FIGS. 21 a  and  21   b  form a flowchart of the Call Processing Facility—Meet Me Caller Function; 
     FIG. 22 is a flowchart of the Call Processing Facility—‘Send Page’ Subroutine; 
     FIGS. 23 a  and  23   b  form a flowchart of the Call Processing Facility—Command Mode Function; 
     FIG. 24 is a flowchart of the Call Processing Facility—Command Message Center Function; 
     FIG,  25  is a flowchart of the Call Processing Facility—Command Forwarding Number Function; 
     FIG. 26 is a flowchart of the Call Processing Facility—Command Feature Timer Function; 
     FIG. 27 is a flowchart of the Call Processing Facility—Command Memory Function; 
     FIG. 28 is a flowchart of the Call Processing Facility—Command Outside Call Function; 
     FIG. 29 is a flowchart of the Call Processing Facility—Command Help Function; 
     FIG. 30 is a flowchart of the Call Processing Facility—Command Meet Me Function; 
     FIGS. 31 and 31 a  form a flowchart of the Call Processing Facility—Command Branch Route Function; 
     FIG. 32 is a flowchart of the Call Processing Facility—Command Advanced Features Function; 
     FIG. 33 is a block diagram illustrating the principle components of the Meet Me Facility; 
     FIG. 34 is a flowchart of the Meet Me Facility Main Task; 
     FIG. 35 is a block diagram illustrating the principle components of the Subscriber Access Facility; 
     FIG. 36 is a flowchart illustrating operation of the E &amp; M Control Circuit for the Subscriber Access Facility; 
     FIGS. 37 a ,  37   b  and  37   b - 1  form a flowchart of the Subscriber Access Facility Main Task; 
     FIG. 38 is a block diagram illustrating the principle components of the Communicator Access Facility; 
     FIG. 39 is a flowchart of the Communicator Access Facility Main Task; 
     FIGS. 40 and 40 a  form a flowchart of the Communicator Main Task; 
     FIG. 41 is a block diagram illustrating the principle components of the Pager Dialing Facility; 
     FIG. 42 is a flowchart of the Pager Dialing Facility Main Task; 
     FIG. 43 is a block diagram illustrating the principle components of the Client Services Facility; and 
     FIG. 44 is a flowchart of the Client Services Facility Main Task. 
    
    
     SPECIFICATION 
     Overview 
     FIG. 1 illustrates in block diagram form, the manner in which the Telephone Control System may be used to enhance the accessibility of it&#39;s subscribers. 
     As shown, the Telephone Control System  1  connects with the PSTN  2  via Facilities  3 . The Telephone Control System  1  may control switch  4 , causing it to connect incoming and outgoing trunks. 
     As is shown, alternate preferred embodiments exist with respect to switch  4 . 
     In the first preferred embodiment, the switch  4  is actually part of the PSTN  1 . In this embodiment, the facilities  3  must be capable of transmitting switch control signals from the Telephone Control System  1  to the switch  4 . An example of this type of facility is a CENTREX line, which allows the transmission of switch control signals in the form of ‘hookswitch flashes’ and touch tones to initiate call-conferencing and call-transfer. A recently available variation of the CENTREX facility is a CENTREX DID trunk, which not only has the ‘hookflash’ capability, but also provides the called number in the form of Direct-Inward-Dialing digits. This is the form of facility  3  which is referred to in the detailed description of the preferred embodiment. Another variation of the CENTREX facility provides the called number via a separate data-link as Simplified Message Desk Interface (SMDI). 
     Copending U.S. application Ser. No. 06/841,931, which issued Jan. 9, 1990, as U.S. Pat. No. 4,893,335, incorporated by reference herein, describes in detail a system for controlling the PSTN switch. 
     In an alternate preferred embodiment, the switch  4  is part of the Telephone Control System  1 . In this embodiment, the facilities  3  need only include standard DID trunks for the incoming calls, and standard outgoing trunks. The access control system  1  controls switch  4  directly, causing it to connect paths between various incoming and outgoing trunks as required. 
     Again referring to FIG. 1, the Telephone Control System  1  also connects to the PSTN  2  via standard tip-ring phone lines  5 , for purposes of communicating with Paging System  6 . The Paging System may be any of the commonly known paging systems such as those comprised of transmitters such as Motorola&#39;s PACE or Quintron model QT250B and paging terminals such as Glenayre model GL3000XL or BBL System  3 , which send encoded messages via radio frequency to cause a unique pager, or beeper, worn by a paging system subscriber, to sound an alert, produce a message in a display, activate a light, vibrate, or produce any of a variety of other alerting mechanisms. Typically, these paging systems will cause a pager to be alerted in response to another individual dialing a phone number which corresponds to that individual&#39;s pager. This phone number is routed via the PSTN  2  to a paging terminal via facilities  7 , which in turn determines, typically via DID digits, who the call is intended for, and then sends a radio frequency message to alert that individual&#39;s pager. To cause a subscriber&#39;s pager to be activated, the Telephone Control System  1  then need only come off hook on one of the lines  5 , and dial the phone number that corresponds to the subscriber&#39;s pager. Although not described in this preferred embodiment, it is anticipated that the Telephone Control System  1  could also interface to a paging system directly via a dedicated data link. 
     An additional facility  5  connects the Telephone Control System  1  to the PSTN  2 . This facility is a trunk which provides the Automatic Number Identification (ANI) of the calling party. An example of such a trunk is the Feature Group D (FGD) trunk which is commonly used by interexchange carriers. The interexchange carriers use the ANI information to properly bill the calling party. The Telephone Control System  1  uses this ANI information in a new and different manner. As will be described in further detail herein, subscribers of the Telephone Control System  1  may program the Telephone Control System  1  by calling it through trunking facilities  5 . The access control system  1  automatically acquires the ANI, or phone number of the calling party. This allows the access control system  1  to program the forwarding number for the subscriber without the subscriber needing to manually enter it. Although not described in the preferred embodiment, it is anticipated that other types of facilities which provide ANI information may also be used for this purpose. An example of another type of facility which provides ANI is a CENTREX line with an SMDI data link, which is now available from several types of central offices. The SMDI data link is capable of passing both the called party number and the calling party number (ANI). 
     Still referring to FIG. 1, The Telephone Control System  1  is also connected to a Packet Radio Transmitter/Receiver  9  via data-link  10 . The Packet Radio Transmitter/Receiver  9  may consist of any of the commonly known radio transceivers such as YAESU FT-470 and  1  COM IC-u 4AT, equipped with a packet radio interface such as HEATHKIT HK-21. As will be described in further detail herein, the Packet Radio Transmitter/Receiver  9  is used by the Telephone Control System  1  to interface. with the portable Communicator device  11 , carried by an Telephone Control System subscriber. The Communicator  11  may both send and receive DATA messages via radio frequency. The Communicator  11  may also receive ultrasonic messages from fixed ultrasonic transmitter  12 , shown located in room  13 . Ultrasonic transmitter  12  continuously transmits the phone number, and, if appropriate, the extension, of the phone  14  located in the same room or a signal indicating an appropriate call control mode for a given situation such as do not disturb in a hospital operating room. It should be noted that, although the preferred embodiment disclosed herein describes transmitter  12  as ultrasonic, it is anticipated that an infrared transmitter may also be used. The ultrasonic transmitter has the advantage that it will pass signals through a layer of clothes, which would be important for example if the subscriber were carrying the Communicator  11  in a shirt pocket. 
     To aide in the discussion of the illustrative examples which follow, FIG. 1 also shows a subscriber&#39;s home  15 , with a home phone  16 ; a subscriber&#39;s office  17 , with an office phone  18 ; a cellular telephone system  19 , which interfaces to a subscriber&#39;s car-phone  20 ; a factory  21 , with a factory phone  22 ; a pay telephone  23 ; a subscriber  24  with pager  25 ; and a caller&#39;s telephone  26 . 
     The illustrative examples which follow are intended only to clarify some of the concepts, features, and objects of the invention, and do not define the scope of the invention. 
     In the examples, the greetings include the phrase “ACCESSLINE”. It should be understood that the phrase “ACCESSLINE” is a registered trademark of AccessLine Technologies, Inc., and therefore those practicing the present invention will need to select alternate terminology if they are not licensed to use that phrase. 
     Methods of Call-Handling 
     Following are several illustrative examples of the various call-handling modes of the Telephone Control System  1 . 
     Direct Forwarding 
     For the sake of this example, assume that a caller at phone  26  wishes to speak to a subscriber to the access control system  1 , and further assume that the subscriber is at home  15 , and that he has preprogrammed the system to ‘direct forward’ his calls to him at his home phone  16 . The caller dials the access number for the subscriber, and the PSTN delivers the call to the Telephone Control System  1  via facilities  3 . The facilities  3  provide the access control system  1  with the called party information (DID) digits. The Telephone Control System then refers to it&#39;s internal database to determine how to handle the call. The access control system determines that calls for this subscriber are to be handled via ‘direct forwarding’ mode, and that the call is to be forwarded to the subscriber&#39;s home. The access control system then dials the subscriber&#39;s home on an outgoing facility  3 , and instructs the switch  4  to connect the incoming facility to the outgoing facility to complete the call. The PSTN  2  then delivers the call to home phone  16 , causing it to ring, and the subscriber may pick up the phone and connect to the caller. Note that this mode of call-handling is referred to as ‘direct forwarding’ because the call is forwarded without any announcement or prompting from the Telephone Control System  1 . 
     Announced Forwarding 
     Assume again that a caller at phone  26  wishes to speak to a subscriber to the Telephone Control System  1 . Also assume that the subscriber is at home  15 , and that this time he has preprogrammed the system to ‘Announce-forward’ his calls to him at his home phone  16 . Again, the caller dials the access number for the subscriber, and the PSTN delivers the call to the Telephone Control System  1  via facilities  3 . Upon receiving the DID digits for this subscriber, the Telephone Control System  1  determines that calls for this subscriber are to be handled via ‘announced forwarding’ mode, and that the call is to be forwarded to the subscriber&#39;s home. The access control system then plays a brief greeting to the caller: “Hello, you have reached the **ACCESSLINE** for Mr. Jones. We&#39;re Connecting your call.” The Telephone Control System then dials the phone number for phone  16  on an outgoing facility  3 , and instructs the switch  4  to connect the incoming facility to the outgoing facility to complete the call. The PSTN  2  then delivers the call to home phone  16 , causing it to ring, and the subscriber may pick up the phone and connect to the caller. 
     Forwarding with Page 
     Assume again that a caller at phone  26  wishes to speak to a subscriber to the Telephone Control System  1 . Also assume again that the subscriber is at home  15 , and that this time he has preprogrammed the system to ‘Forward with page’ his calls to him at his home phone  16 . Again, the caller dials the access number for the subscriber, and the PSTN delivers the call to the Telephone Control System  1  via facilities  3 . Upon receiving the DID digits for this subscriber, the access control system  1  determines that calls for this subscriber are to be handled via ‘forward with page’ mode, and that the call is to be forwarded to the subscriber&#39;s home. The access control system then plays a brief greeting to the caller: “Hello, you have reached the **ACCESSLINE** for Mr. Jones. We are sending a page to inform your party of the call. Please stay on the line.” The Telephone Control System  1  then dials the phone number for the pager corresponding to this subscriber and informs the caller “We have sent a page to alert your party and will connect you momentarily.” The access control system then dials the phone number for phone  16  on an outgoing facility  3 , and instructs the switch  4  to connect the incoming facility to the outgoing facility to complete the call. The PSTN  2  then delivers the call to home phone  16 , causing it to ring, and the subscriber may pick up the phone and connect to the caller. The subscriber, having been alerted to the incoming call by his pager, was ready to receive it. 
     Message Center 
     In some cases the subscriber may not be able to take calls and may wish that his callers simply leave a message. In these cases, the subscriber may program the access control system  1  to connect calls to the subscriber&#39;s preselected ‘message center’. The Telephone Control System  1  may connect calls to either an ‘internal message center’ or an ‘external message center’. The ‘external message center’ is simply a phone number that the Telephone Control System  1  will forward calls to if in this mode. This may be the phone number for an answering service, a receptionist, a voice mail system, or any other appropriate location as desired by the subscriber. If the subscriber elects to use the ‘internal message center’, then an example of a typical call may be as follows. 
     Assume that a caller at phone  26  wishes to speak to a subscriber to the Telephone Control System  1 . Also assume that the subscriber does not wish to be disturbed and that he has programmed the system to ‘internal message center’ mode. The caller dials the access number for the subscriber, and the PSTN delivers the call to the Telephone Control System  1  via facilities  3 . Upon receiving the DID digits for this subscriber, the Telephone Control System  1  determines that calls for this subscriber are to be handled via ‘internal message center’ mode. The Telephone Control System then plays a brief greeting to the caller: “Hello, you have reached the **ACCESSLINE** for Mr. Jones. Your party is not readily available at the moment, however we will connect you to your party&#39;s message center where you may leave a detailed message . . . Please leave your message at the tone.” The Telephone Control System  1  then records the callers message and saves it for later playback by the subscriber. In addition, should the subscriber have so elected, the access control system  1  may dial the phone number corresponding to the subscriber&#39;s pager, to alert the subscriber to the message. 
     Priority-Call Screening 
     Assume again that a caller at phone  26  wishes to speak to a subscriber to the Telephone Control System  1 . This time assume that the subscriber is at his office  17 , and that he has preprogrammed the system to send his calls to him at his office via ‘priority call-screening’, with a message asking the caller to ask for extension 123, which in this example is the extension number of the phone  18  on his desk. Again, the caller at phone  26  dials the access number for the subscriber, and the PSTN  2  delivers the call to the access control system  1  via facilities  3 . Upon receiving the DID digits for this subscriber, the Telephone Control System  1  determines that calls for this subscriber are to be handled via ‘priority call-screening’ mode, and that the call is to be forwarded to the subscriber&#39;s office. The access control system  1  then plays a brief greeting to the caller: “Hello, you have reached the **ACCESSLINE** for Mr. Jones. Your party is not readily available at the moment. If this call is urgent then please touch 0 now and we will attempt to connect you to your party. Otherwise, please hold the line and we will connect you to your party&#39;s message center where you may leave a detailed message.” If the caller does not touch 0, then the call is delivered to the ‘message center’ as described above. If the caller does touch 0, then the Telephone Control System  1  may inform the caller: “Please standby while we connect your call. When the call is answered please ask for extension number 123.” The access control system then dials the preprogrammed lead phone number for the subscriber&#39;s office  17  on an outgoing facility  3 , and instructs the switch  4  to connect the incoming facility to the outgoing facility to complete the call. The PSTN  2  then delivers the call to the receptionist at office  17 , causing it to ring. When the receptionist answers, the caller will ask for extension  123 , as he was instructed by access control system  1 , and the receptionist may connect the call to the subscriber&#39;s desk phone  18 . 
     VIP Code Screening 
     Assume again that a caller at phone  26  wishes to speak to a subscriber to the Telephone Control System  1 . This time assume that the subscriber is in his car, and that he has preprogrammed the system to send his calls to him at his car-phone  20  via ‘VIP code-screening’. In this mode, only those callers who have been told a special VIP code will be able to reach the subscriber. All other callers will be sent to the message center. Again, the caller at phone  26  dials the access number for the subscriber, and the PSTN  2  delivers the call to the Telephone Control System  1  via facilities  3 . 
     Upon receiving the DID digits for this subscriber, the access control system  1  determines that calls for this subscriber are to be handled via ‘VIP code-screening’ mode, and that the call is to be forwarded to the subscriber&#39;s car phone  20 . The Telephone Control System  1  then plays a brief greeting to the caller: “Hello, you have reached the **ACCESSLINE** for Mr. Jones. Your party is not readily available at the moment. Please enter your VIP code now, or hold the line and we will connect you to your party&#39;s message center where you may leave a detailed message.” If the caller does not enter the correct VIP code, then the call is delivered to the ‘message center’ as described above. If the caller does enter the VIP code, then the Telephone Control System  1  may inform the caller: “Please standby while we connect your call.” The Telephone Control System then dials the telephone number for car-phone  20  on an outgoing facility  3 , and instructs the switch  4  to connect the incoming facility to the outgoing facility to complete the call. The PSTN  2  then delivers the call to the cellular telephone system  19 , which in turn delivers the call to the car-phone  20 . 
     Voice-Screening 
     Assume again that a caller at phone  26  wishes to speak to a subscriber of the Telephone Control System  1 . This time assume that the subscriber, Mr. Jones, is visiting his client&#39;s factory  21 , and that he has preprogrammed the system to send his calls to him at this location via ‘voice-screening’. Again, the caller at phone  26  dials the access number for the subscriber, and the PSTN  2  delivers the call to the access control system  1  via facilities  3 . Upon receiving the DID digits for this subscriber, the Telephone Control System  1  determines that calls for this subscriber are to be handled via ‘voice-screening’ mode, and that the call is to be forwarded to his client&#39;s factory  21 . The access control system  1  then plays a brief greeting to the caller: “Hello, you have reached the **ACCESSLINE** for Mr. Jones. Please state your name and the purpose of your call at the tone. After the tone, please stay on the line while we attempt to locate your party and connect your call.” The access control system  1  then records the caller&#39;s name and business, and then responds: “Thank you, please standby.” The access control system then dials the telephone number for factory  21  on an outgoing facility  3 , leaving the incoming call on hold. The PSTN  2  then delivers the outgoing call to the lead telephone number of factory  21 , which is answered by the factory&#39;s receptionist. The Telephone Control System tells the receptionist “We have a call holding for Mr. Jones. Please locate the party.” The receptionist pages Mr. Jones via the factory&#39;s speaker system, informing him of the call. Mr. Jones then answers the call at phone  22 , and enters his Personal Identification Number (PIN) code. The access control system  1  then plays back the callers name and business. The Telephone Control System  1  then asks Mr. Jones: “Please touch 1 to connect the call, 2 to send the caller away, or 3 to send the caller to your message center.” In this example, Mr. Jones wishes to speak to the caller, so he touches 1. The Telephone Control System  1  instructs the switch  4  to connect the incoming facility to the outgoing facility to complete the call. 
     Branch-Routing 
     Assume again that a caller at phone  26  wishes to speak to a subscriber of the Telephone Control System  1 . This time assume that the subscriber is not a person, but a business; the ABC Factory Company  21 , and that the Telephone Control System  1  has been preprogrammed to handle their calls via ‘branch-routing’ mode. Again, the caller at phone  26  dials the access number for the subscriber, and the PSTN  2  delivers the call to the Telephone Control System  1  via facilities  3 . Upon receiving the DID digits for this subscriber, the Telephone Control System  1  determines that calls for this subscriber are to be handled via ‘branch-routing’ mode. The Telephone Control System  1  then refers to it&#39;s memory and plays a pre-recorded ‘branch-routing’ greeting to the caller: “Hello, you have reached the ABC Factory Company. Please touch 1 to speak to the manufacturing manager, 2 to speak to accounts receivable, 3 to speak to accounts payable, 4 to speak to purchasing, or hold the line to speak to the receptionist.” Should the caller need help, he will hold the line for a moment, and the Telephone Control System  1  responds: “Please standby.” The Telephone Control System then dials the telephone number for the factory&#39;s reception phone  22  on an outgoing facility  3 , and instructs the switch  4  to connect the incoming facility to the outgoing facility to complete the call. 
     Meet-Me 
     Assume again that a caller at phone  26  wishes to speak to a subscriber to the Telephone Control System  1 . This time assume that the subscriber, Mr. Jones, is away from the office today, and that he has preprogrammed the system to handle his calls via ‘meet-me’ mode. Again, the caller at phone  26  dials the access number for the subscriber, and the PSTN  2  delivers the call to the Telephone Control System  1  via facilities  3 . Upon receiving the DID digits for this subscriber, the Telephone Control System  1  determines that calls for this subscriber are to be handled via ‘meet-me’ mode. The Telephone Control System  1  then responds by producing audible ringback to the caller, while dialing the phone number for the pager corresponding to this subscriber on facilities  5 . The Telephone Control System  1  then plays a brief message to the caller: “Hello, you have reached the **ACCESSLINE** for Mr. Jones. We are paging your party to a phone, please standby. If you are unable to wait you may touch 9 to leave a message. Otherwise please hold the line.” The Telephone Control System  1  then places the caller on hold and waits for the subscriber to call in. Meanwhile the subscriber  24  has received the page via his pager  25 , and is proceeding to pay phone  23  to answer the call. The subscriber dials his own access number and the PSTN  2  delivers the call to the Telephone Control System  1  via facilities  3 . The subscriber then enters his own PIN code and is informed “You have a caller holding for you on your meet-me service. Please touch 4 to be connected to the caller.” It is also anticipated that if the caller had hung up or left a message in the meantime, that the subscriber would be so informed. Assuming that the caller is still holding, and that the subscriber touches 4, the access control system  1  instructs the switch  4  to connect the incoming facility to the outgoing facility to complete the call. 
     Methods of Programming 
     Although various methods of ‘remotely programmable call forwarding’ have been attempted in the prior art, these have proven to have limited widespread appeal due to the complicated and inflexible methods by which the users were required to program the systems. By contrast, the access control system employs a variety of different methods to allow the subscriber to easily and effectively program the operation of the Telephone Control System. Following are several illustrative examples of the various methods a subscriber may employ to program the Telephone Control System  1 . 
     Command Mode 
     To use the Command Mode method of programming, the subscriber simply dials his own access number from any telephone, and enters his PIN code. The PSTN  2  delivers the call to the Telephone Control System  1  via facilities  3 . The Telephone Control System  1  then informs the caller of the current feature which is selected, and then provides the subscriber with a simple menu of options by which he can chose a new feature. For example, in response to the entry of the PIN code, the subscriber may be prompted: “Hello Mr. Jones. Your calls are currently being VIP code screened to your office. Touch 1 to check messages, 2 to change your forwarding number, 3 to select a memory, 8 for advanced features, 9 to make a call, or touch 0 for help.” The subscriber may then make his desired selection. Please note that although the preferred embodiment herein discusses the use of touch tone as the signalling method by which the subscriber controls the Command Mode of the access control system, the inventors anticipate that other signalling methods may also be employed, including, but not limited to, rotary dial pulse detection and voice recognition. 
     Another feature of the Telephone Control System Command Mode allows the subscriber to program ‘mode memories’ which contain the most often used call handling methods for that subscriber. For example, a subscriber may program memory  10  to be announced forwarding to his office, memory  20  to be voice screened forwarding to his home, memory  30  to be message center mode, and so forth. 
     Weekly Schedule 
     Subscribers who have some routine to their weekly activities may soon grow weary of constantly calling the Telephone Control System and selecting the same call handling methods at the same time, day after day. For this reason, the weekly schedule feature provides a very real benefit to the subscriber. As an example, let us assume that a subscriber, Mr. Jones, starts work at 8:00 AM every morning, and leaves for home at 5:00 PM in the evening. Let us further assume that he takes an hour for lunch from 12:00 to 1:00 PM each day. The weekly schedule for this subscriber might be pre-programmed into the Telephone Control System&#39;s database to be: 
     
       
         
               
               
               
               
             
           
               
                   
               
               
                 DAY 
                 TIME 
                 MODE MEMORY 
                 FEATURE 
               
               
                   
               
             
             
               
                 Mon-Fri 
                 7:30 am 
                 30 
                 Message Center 
               
               
                 Mon-Fri 
                 8:00 am 
                 10 
                 Announced forwarding 
               
               
                   
                   
                   
                 to office 
               
               
                 Mon-Fri 
                 12:00 noon 
                 30 
                 Message center 
               
               
                 Mon-Fri 
                 1:00 pm 
                 10 
                 Announced forwarding 
               
               
                   
                   
                   
                 to office 
               
               
                 Mon-Fri 
                 5:00 pm 
                 20 
                 Voice screen 
               
               
                   
                   
                   
                 forwarding to home 
               
               
                   
               
             
          
         
       
     
     As calls are received by the Telephone Control System for this subscriber, the Telephone Control System  1  refers to this database and determines the correct call handling method for the day of week and time of day, and delivers the call accordingly. 
     Another feature of the weekly schedule allows the subscriber to override the weekly schedule should his schedule deviate from the preprogrammed sequence. In this way the subscriber can move freely about his routine activites, and only he needs to program the access control system should his schedule change from the normal. 
     Feature Timer 
     To illustrate the use of the Feature Timer capability of the Telephone Control System, assume that a subscriber is visiting a client&#39;s office for a one hour appointment, and wishes to have his calls forwarded to him at this location during that time. He may use the Command Mode as described above to select announced forwarding mode and change the forwarding number to be the telephone number of his client&#39;s phone. When he leaves he intends to change the the call handling mode back to his message center. However, if the subscriber forgets to call the Telephone Control System as he is leaving the client&#39;s office, then the client may still continue to receive calls intended for the subscriber. To overcome this problem, the subscriber may have instead used the Feature Timer function when he first called the access control system when he got to the client&#39;s office. In this example, the subscriber could have called the access control system, and used Command Mode to select announced forwarding to his client&#39;s office. However, instead of hanging up at that point, he could have activated the Feature Timer, programming it to maintain the current mode for one hour and then automatically change the call handling mode to message center mode. In this way, the subscriber would not have to remember to call the Telephone Control System as he leaves the client&#39;s office, and the client would not be bothered with the subscriber&#39;s calls after he left. 
     Programming a Forwarding Number Using ANI 
     One difficulty in prior art implementations of remotely programmable call forwarding devices, is that it takes quite a few digits for the user to call the system, enter an access code, and then enter the forwarding number. One means by which the invention described herein overcomes this difficulty is by employing special trunks which provide the called party number, also referred to as ANI. To see how this improves the ease of programming, consider the following example. Assume that the subscriber is visiting factory  21 , and that this is a location that he does not visit regularly, and therefore does not have it&#39;s telephone number preprogrammed into the Telephone Control System  1 . Further assume, as was discussed earlier, that the access control system  1  is connected to the PSTN with Feature Group D trunks  8  which provide ANI, and which can be reached by dialing an 800 number. To cause his calls to get to him at the factory  21 , the subscriber in this example would pick up telephone  22  and dial the 800 number which corresponds to the Feature Group D trunk. The PSTN  2  would deliver the call to the Telephone Control System  1  and the Telephone Control System  1  would receive the ANI information digits containing the telephone number of telephone  22 . The subscriber then need only enter his PIN code and the call handling feature memory he wishes to use, which might be memory  40 , announced forwarding. The subscriber could then hang up and the Telephone Control system  1  would program the database to send all calls for that subscriber to telephone  22  via announced forwarding. As should be obvious, the sequence of digits entered by the subscriber was shorter than if he had to actually enter the phone number. It should also be pointed out that another advantage of this method of programming is that the same sequence of digits is used to program the system each time. In other words, if the subscriber went to another location and wanted his calls to be sent to him via announced forwarding, he could pick up a phone and dial the exact same sequence of digits as was described above. This makes the programming of the Telephone Control System less demanding on the subscriber since he only has to memorize one sequence to accomplish this function. It is also anticipated by the inventors that a subscriber to this service may employ a ‘pocket dialer’ preprogrammed with this fixed digit sequence, thereby even further simplifying the ease of programming. 
     Programming the Telephone Control System Using Speed Calling and ANI 
     A well known service offered by many telephone companies is ‘Speed Calling’. This service allows users to preprogram often used telephone numbers into memories which can be recalled by dialing a one, two, or three digit code. To see how subscribers can use this service to improve the ease of programming the Telephone Control System, consider the following example. Assume that an Telephone Control System subscriber, who lives at home  15 , has preprogrammed the access control system with his home phone number  16 . Let us further assume, as was discussed earlier, that the Telephone Control System  1  is connected to the PSTN  2  with Feature Group D trunks  8  which provide ANI, and which can be reached by dialing an 800 number, and assume further that an entire 800-NNX has been dedicated to this trunk group, in this example 800-999-XXXX. By this invention, the last four digits of the 800 number will be used to signify the mode memory which is being selected. In this example, also assume that the subscriber has preprogrammed his telco speed dialing feature so that the sequence 2# causes the telephone number 1-800-999-0010 to be dialed, and that the sequence 3# causes the telephone number 1-800-999-0011 to be dialed. In this example, when the subscriber picks up telephone  16  and dials 2#, the speed dialing feature will cause the number 1-800-999-0010 to be dialed. The PSTN  2  will deliver the call to the access control system  1  via Feature Group D trunks  8 . The access control system  1  will receive the ANI digits, and referring to it&#39;s database recognize the call as originating at the home telephone of one of it&#39;s subscribers. It then will invoke the preprogrammed mode memory  10  for that subscriber, which in this example might be voice-screened forwarding to his home phone. As a further example, if the subscriber had dialed 3#, the Telephone Control System  1  would have invoked memory  11  for that subscriber. 
     Communicator 
     As described earlier, the Communicator is a portable device carried on the subscriber&#39;s person. This example demonstrates some of the ways by which the Communicator can simplify the call handling and programming operations for the Telephone Control System subscriber. Still referring to FIG. 1, assume that the subscriber is carrying a communicator  11  on his belt, and that he has just entered room  13 . Also assume that he has selected the ‘automatic phone number’ mode of operation for the Communicator  11 . When he enters the room, the Communicator  11  detects a signal from the fixed ultrasonic transmitter  12  located near the ceiling. This signal is decoded by the Communicator  11  and is determined to contain a phone number, which in this example happens to correspond to the phone instrument  14  located in the same room  13 . Upon receipt of the ultrasonic signal, the Communicator  11  transmits a brief packet message via radio frequency. This message contains the subscriber&#39;s access number and the phone number just received form the ultrasonic transmitter  12 . This radio frequency message is detected by packet radio transceiver  9  and passed on to the access control system  1  via data link  10 . The Telephone Control System  1  then changes the forwarding number for this subscriber to be the new number. 
     Assume now that a caller at phone  26  wishes to speak to this subscriber. The caller dials the access number for the subscriber, and the PSTN delivers the call to the access control system  1  via facilities  3 . Upon receiving the DID digits for this subscriber, the Telephone Control System  1  determines that calls for this subscriber are to be handled via ‘direct forwarding’ mode, and that the call is to be forwarded to the subscriber at telephone  14 . The access control system  1  then sends a page message to the packet radio transceiver  9  via data-link  10 . The packet radio transceiver  9  in turn transmits a radio frequency packet message to Communicator  11 , causing the beeper in the Communicator  11  to alert the subscriber to the incoming call. The Communicator  11  may also then send an acknowledgment message back via radio frequency to the packet radio transceiver  9 . Meanwhile, the Telephone Control System  1  has begun to dial the phone number for phone  14  on an outgoing facility  3 , and instructs the switch  4  to connect the incoming facility to the outgoing facility to complete the call. The PSTN  2  then delivers the call to phone  14 , causing it to ring, and the subscriber may pick up the phone and connect to the caller. Continuing the illustrative example, assume that the subscriber completes the call and leaves the room  13 . Communicator  11  detects the loss of signal from ultrasonic transmitter  12 , and realizes therefore that the subscriber has left the room and is no longer able to receive calls at this location. The Communicator  11  then transmits a brief packet message via radio frequency. This message contains the subscriber&#39;s access number and a special message indicating that no phone number is available and that a default mode memory is to be used for call handling. This radio frequency message is detected by packet radio transceiver  9  and passed on to the Telephone Control System  1  via data link  10 . The Telephone Control System  1  then changes the method of call handling for this subscriber to the default mode, which may typically be message center mode. It should be obvious now that if the subscriber were to reenter room  13 , or to enter another room with a similar ultrasonic transmitter, that a similar sequence of events would occur causing the calls for this subscriber to be routed to the appropriate room. In this way, without any specific action or effort on the part of the subscriber, his calls will follow him from location to location and be handled automatically and properly. 
     Another feature of the Communicator allows the subscriber to enter a ‘manual phone number’ mode whereby the Communicator will ignore the messages received from the ultrasonic transmitters, maintaining the last used mode or forwarding number. 
     Another feature of the Communicator allows the subscriber to select a new method of call-handling by touching keys on the Communicator&#39;s keypad. This will cause the Communicator  11  to transmit a ‘new mode memory request’ packet message via radio frequency to the packet radio transceiver, which in turn will send the message to Telephone Control System  1  via data-link  10 , causing the Telephone Control System  1  to change the call handling method for that subscriber. 
     DETAILED DESCRIPTION 
     FIG. 2 is a block diagram of the telephone control system  1 . The preferred embodiment of the telephone control system  1  consists of a variety of subsystems, or facilities. A Call Processing Facility (CPF)  100  is shown connected to trunks  3 . A Pager Dialing Facility (PDF)  105  is shown connected to telephone lines  5 . A Subscriber Access Facility (SAF)  110  is shown connected to trunks  8 . A Meet-Me Facility (MMF)  115  is shown connected to lines  120 . A Communicator Access Facility (CAF)  125  is shown connected to datalink  10 . A Client Services Facility (CSF)  130  is also shown. Each of these facilities is connected to high speed data network  150 . 
     A block diagram of the Communicator  11  is shown in FIG.  3 . The operation of the Communicator  11  is controlled by microprocessor  200 , which in the preferred embodiment is a single chip microprocessor containing it&#39;s own Read-Only-Memory (ROM) and Random-Access-Memory (RAM). A keypad  205 , and display  210  are shown connected to microprocessor  10 . A transmit data output port  215  is provided by the microprocessor  200 . This transmit data is passed to packet data encoder  220  which formats the data into packets before sending the packets to antenna  230  via radio frequency transmitter  225 . Radio frequency receiver  235  receives data packets from antenna  230  and passes them to packet data decoder  240 , which removes the packet format and passes the raw received data to the receive data input port  245  on microprocessor  200 . Output port  250  may be used to apply a tone signal to beeper driver  255  which supplies sufficient current to drive beeper  260  to produce an alerting sound. A transducer  265 , capable of receiving signals in the ultrasonic frequency range, passes these signals to a 40 Kilohertz filter and amplifier  270 . The resulting signal is applied to detector  275  which removes the 40 Kilohertz component from the signal and passes the resulting serial data to input port  280  of microprocessor  200 . Also shown is a crystal oscillator  285  which controls the timing of all operations of the microprocessor  200 . Power for the Communicator  11  is supplied by battery  290 . Improvements that currently exist in the ART may be made to the ultrasonic transmitter and detector to enhance its ability to communicate the ultrasonic data in the presence of multi-path echoes. These improvements include, but are not limited to: frequency shift keying; the transmission of synchronized data and the use of a clock recovery logic to extract the clock timing over a long integration period resulting in a clock move resistant to echoes; the use of error detecting and correcting codes; and the use of sampling and voting techniques to determine the correct bit value after multiple samples during a bit period, the bit period being determined by the clock recovery logic above. In addition, multiple transmitters may be used as a method of obtaining increased coverage and area transmission diversity. 
     A block diagram of the Ultrasonic Transmitter  12  is illustrated in FIG.  4 . Oscillator  300  provides a 40 Kilohertz signal to one input of AND gate  305 . The output of crystal oscillator  310  is applied to divider  311  which produces a 75 Hertz signal to the clock input of 6-bit counter  315 . The 6 outputs of counter  315  are applied to the address inputs of Read-Only-Memory  320 . Memory  320  is pre-programmed with data representing the phone number of the nearest telephone. This data may contain the area code plus seven digits and the extension number if appropriate. With each digit represented by 4 bits, 14 digits and 8 bits of checksum may be transmitted. Only the least significant bits in ROM  320  need be programmed, as the LSB output  325  is used to apply this data to a second input of AND gate  305 . As can be seen, the serial data at  325  will continuously output the- phone number at a rate of 75 bits per second. AND gate  305  combines the serial data  325  and the 40 Kilohertz signal from oscillator  300  producing a resultant signal which is applied to transducer driver  330 . The output of driver  330  is then applied to transducer  335 . As should be obvious, the transducer will be generating a 40 Kilohertz signal while the serial data output  325  is high, and will be generating no signal while the serial data output  325  is low. The data is therefore modulated on the 40 Kilohertz carrier at a rate of 75 baud. The 64 bits from the ROM  320  are thus transmitted in a period of 0.853 seconds. This is adequate for the transmission of a phone number and extension. Although this baud rate is relatively low; it has the advantage of reducing the effect of multipath (reflections of the ultrasonic signal arriving at the receiver at different times and phases), and thus improves the reliability of transmission as compared with higher baud rates. 
     A block diagram of the Call Processing Facility (CPF)  100  is shown in FIG. 5.. 
     Referring to FIG. 5, CPF trunk interface  400  interfaces the CPF  100  with trunk  3 . As was discussed earlier, the preferred embodiment of the telephone control system  1  employs a CENTREX DID trunk. In this embodiment trunk  3  is provided via a 4-wire E&amp;M trunk provisioned with TYPE I signalling, which is well known in the art. This type of trunk provides a 2-wire balanced transmit audio connection, shown terminated by line termination  405 . This type of trunk also provides a 2-wire balanced receive audio connection, shown terminated by line termination  410 . The E-Lead of trunk  3  is shown connected to the current limiting and overvoltage protection at reference  415 . In a similar fashion, the M-Lead of trunk  3  is shown connected to the current limiting and overvoltage protection at reference  420 . 2-to-4 wire convertor  425  takes the separate balanced transmit and receive signals from line terminators  405  and  410  and combines them into one single-ended signal at reference  430 , which is applied to call processor  435 . The E-Lead signal from limiter/protector  415  is passed to current detector  440 . As is shown, current detector  440  provides a path for the E-Lead signal through to the negative battery reference of −48 volts at  445 . Current Detector  440  also provides an “E-Lead Detect” logic signal indicating the presence of current via the E-lead. This signal is applied to E&amp;M lead control circuit  450 . The M-Lead signal for limiter/protector  420  is passed to M-Lead relay  455 . This relay is controlled by a “M-Lead Control” signal from control circuit  450 . By activating or deactivating relay  455 , control circuit  450  is able to take the M-Lead on-hook or off-hook, as the M-Lead will be connected either to −48 volts or to ground. The control circuit  450  outputs an “Incoming Call” signal  470  to buffer  460 , and outputs a “Loop Status” signal  475  to call processor  435 . The control circuit  450  has as additional inputs a “DID Received” signal  480  from latch  465 , and an “On/Off-Hook Control” signal  485  from call processor  435 . The output of buffer  460 , and the input of latch  465  is applied to CPF internal data bus  490 . 
     Still referring to FIG. 5, the CPF internal data bus  490  connects CPF trunk interface  400 , call processor  435 , precision busy/ring detector  437 , Central Processing Unit (CPU)  495 , Random Access Memory (RAM)  500 , Disk memory  505 , and data network interface  510 . Call processor  435  performs the functions of voice record and playback, dual-tone-multi-frequency (DTMF) detection and generation, and call control. The functions of call processor  435  are well known in the art and many products, such as the Model D41B manufactured by Dialogic Corporation, exist commercially which can accomplish these functions. A voice recognition module  436  is shown connected to call processor  435 . Voice recognition module  436  allows call processor  435  to detect, on a speaker-independent basis, a simple set of spoken commands from callers. The simple set consists of  16  words including the digits ‘0’ through ‘9’. This capability, in combination with the DTMF detection capability of the call processor  435 , allows caller to either speak their commands, or enter them from a DTMF phone. A commercially available product which performs this voice recognition function is the Model VR/10 manufactured by Dialogic Corporation. 
     A precision busy/ring detector  437  is shown connected to the audio signal  430  from CPF trunk interface  400 . This detector may be used to perform a rapid detection of precise busy and precise ringing signals, even in the presence of voice. Unlike the busy and ring detection functions of Call Processor  435  which require a cadence match as well as a frequency match, precision busy/ring detector  437  does not require a cadence match and is therefore capable of rapidly detecting precise busy and ringing signals even if a party is conferenced in and speaking on the line. This capability is useful in providing the ‘busy/no-answer option’ as will be described later. The functions of precise busy/ring detector  437  are well known in the art, and may be typically implemented as follows. The incoming audio signal is applied to the inputs of several identical circuits, each with center frequencies set to detect a different component of the expected busy or ringing signal. Each of these circuits contains a low Q bandpass filter. This filter prevents out-of-band signals such as voice from interfering with the detection function. The output of the bandpass filter is fed to a zero crossing detector. The output of the zero crossing detector is then fed to a high Q bandpass filter again set at the frequency to be detected. The output of the bandpass filter is then sent to a level detector which provides a positive indication if the incoming signal is above a preset amplitude. The output of the busy/ring detector  437  may be read by CPU  495  via the CPF internal data bus  490 . 
     CPU  495  controls all functions of CPF  100 . The software program which the CPU  100  uses is loaded into RAM  500 , from disk memory  505 . The disk  505  also is used to store a variety of other data including the subscriber database for the telephone control system  1 . A data network interface  510  is used to connect the CPF  100  to the other subsystems of the telephone control system  1 . Data network interface  510  passes data messages between the CPU  495  and these other subsystems. The functions of data network interface  510  are well known in the art, and many products, such as the Model COM4i from Digiboard Corporation, exist commercially which can accomplish these functions. Although only one trunk interface  400 , one trunk  3 , and one call processor  435  are shown in FIG. 5, it should be readily evident to one skilled in the art that additional trunk interfaces and call processors may be added to support additional trunks. 
     A flowchart of the operation of E&amp;M control circuit  450  is shown in FIG.  6 . At reference  600 , the control circuit  450  idles waiting for an indication from current detector  440  that the E-Lead has gone off-hook. When the E-Lead does go off-hook, as shown at reference  605 , an “Incoming Call” signal is sent to CPU  495  via buffer  460 . The control circuit  450  then idles at  610 , waiting for an off-hook signal from call processor  435 , signifying that the CPU  495  is ready to accept the call. When the off-hook signal is received, the “Loop Status”  475  is set active as shown at reference  615 . The M-Lead is then winked by taking M-Lead relay  455  momentarily off-hook, as shown at reference  620 . The control circuit  450  then idles again at  625 , waiting for the receipt of the “DID Received” signal  480  from CPU  495  via latch  465 . Call processor  435  detects the incoming DID digits on it&#39;s audio line  430  and decodes the digits passing the digit sequence on to CPU  495 . This DID digit sequence represents the ‘called number’ or ACCESS NUMBER of a subscriber to the telephone control system  1 . When the CPU  495  receives the DID digits from call processor  435 , the CPU  495  sets the “DID Received” signal  480  active, and the control circuit  450  takes the M-Lead off-hook as shown at reference  630 . At this point a call has been established, and the control circuit  450  must now wait until either CPU  495  terminates the call, as signified by on/off-hook control signal  485  going on-hook, or by the calling party terminating the call as signified by the E-Lead detect from current detector  440  going on-hook. These functions are accomplished by control circuit.  450  as illustrated at references  635  through  670 . At  635  a check is made to determine if on/off-hook control signal  485  is on-hook. If it is still off-hdok then a check is made at  640  to determine if the E-lead detect signal is on-hook. If it is on-hook, then the calling party has hung up, and the control circuit  450  sets the “Loop Status”  475  inactive at  645 , signalling the call processor  435  that the call is terminated. The call processor  435  may in turn signal CPU  495  that the call is terminated. Control circuit  450  then waits as shown at reference  650  for the “DID Received” signal  480  to become inactive, signifying that the CPU  495  is completed with the call and is ready to accept a new call. When the “DID Received” signal  480  goes inactive, control passes to step  675  where the M-Lead is placed on hook. Control then returns to step  600  where the control circuit  450  restarts it&#39;s sequence at reference  600 . Returning again to reference  635 , if the On/off-hook control signal  485  were found to be on-hook, then a 1.5 second timer is started as shown at reference  655 . This timer is used to distinguish between a ‘hookflash’ signal, which is typically less than 1.5 seconds, and an on hook command which should be at least 1.5 seconds. At  660 , the control circuit  450  causes the M-Lead relay  455  to place the M-Lead on-hook. At  665  a check is made to determine if the 1.5 second timer has expired. If it has expired, then the signal was a true on-hook command, and control passes to reference  645  for the termination of the call. If at  665  it is determined that the 1.5 second timer has not expired, then a check is made at  670  to determine if the on/off-hook control  485  is still on-hook. If it is still on-hook then the timer is tested again at  665 . If the on/off-hook control  485  is off-hook again, then the command was a flash, and control returns to reference  630 , where the M-Lead is taken off-hook once more. 
     A diagram of the Subscriber Master Record, reference  700 , is illustrated in FIG.  7 . The subscriber master record contains information regarding a given subscriber&#39;s chosen method of call handling. This information is used by the Telephone Control System  1  to determine how to process the call. One unique subscriber master record exists for each subscriber to the Telephone Control System  1 . All subscriber master records are stored in disk  505  and, upon initialization of the Telephone Control System  1 , are copied to a common database in RAM memory  500  by CPU  495 . This facilitates fast retrieval of this information, which is necessary for the real-time processing of calls to the access control system  1 . 
     Still referring to FIG. 7, the subscriber master record  700  contains as it&#39;s first element an access (DID) number, shown at reference  701 . As described earlier, this access number  701  is the unique phone number which is used to reach a given subscriber via the Public Switched Telephone Network  2 . A PIN code, which is used by the subscriber to identify himself to the Telephone Control System  1 , is shown at  702 . At  703 , a call handling mode is shown. The call handling mode defines the basic method of call handling which has been chosen by the subscriber. Possible call handling modes include direct forwarding, announced forwarding, message center, voice screen forwarding, urgent screen forwarding, VIP code screen forwarding, and branch-routing. At  704 , a standard greeting type is shown. The standard greeting type,  704 , defines the courtesy greeting announcement which the subscriber has selected for the Telephone Control System  1  to use when first answering a call. At  705 , an options field is shown. This options field is used to contain several miscellaneous option flags which may be used to modify the operation of the basic call handling mode. Options  705  include ‘page option’ which causes a page to be sent when a call is forwarded, an ‘emergency/urgent’ option which modifies the operation of the priority or urgent screen forwarding mode, a ‘busy/no-answer’ option which causes calls to be sent to the message center if a busy or no-answer condition is detected, and a voice screen hold off option which modifies the operation of the voice screen forwarding mode. A transfer message type is shown at reference  706 . The transfer message type,  706 , defines the courtesy announcement which the subscriber has selected for the access control system  1  to use as a call is being transferred. A transfer number is shown at  707 . This is the number which the access control system  1  will use when forwarding, or transferring calls for this subscriber. At  708  an extension number is shown which may be used by the Telephone Control System  1  to a ounce to a caller the extension number of the phone at which the subscriber is located. The subscriber&#39;s message cater number is shown stored at  709 . The subscriber&#39;s pager number is shown stored at  710 . The subscriber&#39;s office number is shown stored at  711 . The subscriber&#39;s home number is shown stored at  712 . The subscriber&#39;s mobile phone number is shown stored at  713 . At  714  a VIP screen code is shown. The VIP screen code is a code which may be used by a caller to cause his call to be forwarded to the subscriber, when the subscriber has selected VIP code screened forwarding mode. The number of the current feature memory which is being used is shown stored at  715 . At  716  a pager message display number is shown. This is the number which the subscriber wishes to appear in the display of his pager when the access control system  1  has taken a message from a caller. At  717  a pager forwarding display number is shown. This is the number which the subscriber wishes to appear in the display of his pager when the Telephone Control System  1  is in the process of forwarding a call to the subscriber. At  718  a communicator dynamic mode display number is shown. This is the number which the subscriber wishes to appear in the display of his communicator  11  when the Telephone Control System  1  has a call holding, and requires that the subscriber select a method of call handling to dispose of the call. The time and date that the last caller abandoned a meet-me call by hanging up without leaving a message is shown stored at  719 . The time and date that the last caller abandoned a meet-me call by leaving a message is shown stored at  720 . A count of the number of calls which have been transferred to an external message center by the Telephone Control System  1  is shown stored at  721 . Shown generally at  722  are the branch routing numbers 0 through 9. These fields contain the phone numbers to which a call should be transferred if a caller touches one of the digits 0 to 9 when the access control system  1  is processing a call using branch-routing mode. The branch-routing default transfer number is shown stored at  723 . This is the number to which the call is transferred should a caller not enter one of the digits 0 to 9. Shown stored at  724  is the feature timer duration. This value determines when the feature timer expires. Shown stored at  725  is the feature timer termination mode. This field contains the mode memory which the subscriber wishes to use upon expiration of the feature timer. The fields necessary to implement the weekly schedule function are shown generally at reference  726 . In the preferred embodiment the weekly schedule may contain up to 32 events (steps). For each step, the subscriber master record  700  stores a time and date, and a mode memory number to be used at that time and date. The current step number (1 to 32) is shown stored at  727 . A flag which indicates to Telephone Control System  1  that the weekly schedule is on, is shown stored at  728 . A flag which informs the Telephone Control System  1  as to whether the subscriber is allowed to make multiple outside calls is shown stored at  729 . A flag indicating that the subscriber has selected to use his communicator  11  in the ‘dynamic mode assignment’ mode is shown stored at  730 . A count of the number of calls made to this ACCESS NUMBER is shown stored at  731 . 
     A diagram of a Mode Memory, reference  800 , is illustrated in FIG.  8 . As described previously, the mode memories are used by subscribers of the Telephone Control System  1  to store their commonly used call handling modes and options. As with the subscriber master records  700 , the mode memories  800  are stored in disk  505  and, upon initialization of the Telephone Control System  1 , are copied to a common database in RAM memory  500  by CPU  495 . Each mode memory is unique to an individual subscriber, and is identified by storing the subscriber&#39;s ACCESS NUMBER as part of the mode memory, as shown at reference  801 . In the preferred embodiment, the subscriber may have up to 90 mode memories. Each mode memory is identified by a unique mode memory number, 10 through 99. This mode memory number is shown stored as part of the mode memory  800  at reference  802 . Shown generally at reference  803 , are the various fields which the subscriber has selected to store in the mode memory  800 . As can be seen, these are a subset of the fields which are stored in the subscriber master record  700 . To invoke a mode memory, the Telephone Control System  1  need only copy the fields from the mode memory  800  to the corresponding fields in the subscriber master record  700 . The access control system  1  also copies the mode memory number  802  to the current feature memory field  715  of the subscriber master record  700 . 
     A flowchart of the Main Task for the Call Processing Facility (CPF)  100  is shown in FIG.  9 . This flowchart represents the instructions, or steps, followed by CPU  495 , as it controls functions of CPF  100 . The starting point for the CPF—MAIN TASK is shown at reference  900 . At step  901  the CPU  495  performs initialization processes. These processes are well known in the art and include such activities as using a boot PROM to load the operational program from disk, checking for memory errors, performing hardware diagnostics, etc. The subscriber master records  700  are read from disk  505  and copied to a database in memory  500 , as shown at step  902 . In a similar manner, the mode memories  800  are read from disk and copied to a database in memory, as shown at step  903 . At step  904 , the multitasking processes are established. The multitasking allows the software to perform more than one process simultaneously. Multitasking techniques are well known in the art. As an example, UNIX is a widely used multitasking operating system. Other well known techniques allow a pseudo-multitasking function to be accomplished on a non-UNIX based operating system by constructing a ‘round-robin’ scheduler, by which a main process allocates ‘time slices’ to each of a number of sub-processes. At step  905  a process for the Network Message Task is initialized, and at step  906  control is passed to the CPF—Network Message Task. At step  907  a process for the Call Handler Task for the first trunk  3  is initialized, and at step  908  control is passed to the CPF—Call Handler Task. In a similar fashion, at step  909  a process for the Call Handler Task for the last trunk  3  is initialized, and at step  910  control is passed to the CPF—Call Handler Task. At step  911  a process for the Call Termination Task is initialized, and at step  912  control is passed to the CPF—Call Termination Task. 
     A flowchart of the CPF—Network Message Task is illustrated in FIG.  10 . The function of this task is to receive and process messages received by Data Network Interface  510  from other facilities of the access control system  1 . The CPF—Network Message Task is entered at step  1000 . At step  1001  a determination is made as to whether a “request master record” message has been received. If this message has been received, then at step  1002  the subscriber master record  700  which corresponds the DID number, ANI number, or PIN code provided in the message is searched for in the database of memory  500 . Upon finding this subscriber master record, at step  1003  a message containing a copy of this subscriber master record is sent back to the requesting facility via data network interface  510 . Control then returns to step  1000 . Should it be determined at step  1001 , that no “request master record” message has been received, then at step  1004  a check is made to determine if an “update master record” message has been received. If such a message has been received, then at step  1005  a master record for a subscriber is recovered from the message and copied to the the subscriber&#39;s master record  700 , at which point control returns to step  1000 . If an “update master record” message is not detected at step  1004 , then at step  1006  a check is made to determine if a “clear dynamic mode assignment flag” message has been received. If such a message has been received, and the message identifies a specific subscriber DID number, then the dynamic mode assignment flag  730  in the subscriber master record  700  for this subscriber is cleared at step  1007 , and control returns to step  1000 . If a “clear dynamic mode assignment flag” message is not detected at step  1006 , then at step  1008  a check is made to determine if a “set dynamic mode assignment flag” message has been received. If such a message has been received, and the message identifies a specific subscriber DID number, then the dynamic mode assignment flag  730  in the subscriber master record  700  for this subscriber is set at step  1009 , and control passes to step  1000 . If a “set dynamic mode assignment flag” message is not detected at step  1008 , then at step  1010  a check is made to determine if “change to new mode memory” message has been received. If such a message has not been received, then control passes to step  1014 . If such a message has been received, and the message identifies a specific subscriber DID number, then at step  1011  a check is made to determine if the message was sent by the Communicator Access Facility (CAF)  125 . If the message was not from the CAF  125 , then control passes to step  1013 . If the message was from the CAF  125 , then at step  1012  an indication is sent to the CPF—Dynamic Mode Assignment routine (shown in FIG.  13 ), that this message was received, and control passes to step  1013 . At step  1013 , the mode memory number and the subscriber&#39;s DID number are removed from the message, and the corresponding mode memory  800  is copied to the corresponding subscriber&#39;s subscriber master record  700 . Control then returns to step  1000 . If at step  1010  it is determined that a ‘change to new mode memory message’ is not received, then control passes to step  1014 , where a determination is made as to whether a ‘mode memory inquiry’ message is received, and if this is the case then control passes to step  1015  where the mode memory  800  identified in the message for the subscriber identified in the message is retrieved from the database of memory  500  and a message is constructed and sent back to the requesting facility via data network interface  510 . Control then returns to step  1001 . If at step  1014  it is determined that a ‘mode memory inquiry message is not received, then control passes to step  1016 , where a determination is made as to whether a ‘mode memory update’ message is received, and if this is the case, then control passes to step  1017  where the new mode memory contents are retrieved from the message, and the mode memory is copied to the appropriate mode memory  800  in the database of memory  500 . Control then returns to step  1001 . If at step  1016 , it is determined that a ‘mode memory update’ message is not received, then control passes to step  1018  where a determination is made as to whether a ‘create new subscriber’ message is received, and if this is the case then control passes to step  1019  where the DID number is retrieved from the message, a subscriber master record  700  is created for this DID number  701 , and a set of mode memories  800  are created for this DID number  701 . Control then returns to step  1001 . If at step  1018  it is determined that a ‘create master record’ message is not received, then control returns to step  1001 . 
     A flowchart of the CPF—Call Termination Task is illustrated in FIG.  11 . The purpose of this task is to monitor the loop status signal  475  for each trunk interface  400 , and to terminate any call in progress should the loop status become inactive. In this way the system detects if the calling party has hung up. The CPF—Call Termination Task is entered at step  1100 . At step  1101  a trunk pointer is set to a value of 1. At step  1102  the loop status signal  475  for the trunk pointed to by the trunk pointer is read via call processor  435 . At step  1103 , a determination is made as to whether the loop status signal  475  is active. If the signal is active, then control passes to step  1106 . If the signal is not active, then the caller must have hung up, and at step  1104  the trunk is placed on hook by call processor  435  via on/off hook control signal  485 . Then at step  1108  a determination is made as to whether this trunk was processing the “CPF-Meet Me Caller” function, and if this is the case then control passes to step  1109  where the current time and date is stored in the “last meet-me abandon” field  719  of the subscriber master record  700 . Control then passes to step  1105 . Control also passes to step  1105  if at step  1108  it is determined that the trunk was not processing the “CPF-Meet Me Caller” function. At step  1105  this CPU  495  signals the multitasking process  907  controlling the call handler task for this trunk to return to it&#39;s entry point  908 , thereby terminating any activity on that trunk. Control then passes to step  1106 , where a check is made to determine if the trunk pointer is pointing to the last trunk. If the trunk pointer is pointing to the last trunk, then control returns to step  1101 . If the trunk pointer is not pointing to the last trunk, then at step  1107  the trunk pointer is incremented and control returns to step  1102 . 
     A flowchart of the CPF—Call Handler Task is illustrated in FIGS. 12 a  and  12   b . The function of this task is to respond to an incoming call on a trunk  3 , receive the DID digits identifying the subscriber&#39;s ACCESS NUMBER being dialed, determine the method of call handling as specified in the database of memory  500  by subscriber master record  700  which corresponds to that ACCESS NUMBER, and then cause the call to be processed accordingly. The CPF—Call Handler Task is entered at step  1200 , a connection point labelled “CPF IDLE” is passed at reference  1201 , and at step  1202  the DID received signal  480  is cleared, allowing trunk interface  400  to receive a new call. Control then remains at step  1203  until an incoming call signal  470  is received from the trunk interface  400 , at which point control passes to step  1204  causing the call processor to issue an off hook signal via it&#39;s on/off hook control line  485 . Then at step  1205 , incoming DID digits are decoded and accepted by the DTMF detector of call processor  435 . Then at step  1206 , after the DID digits have been received, the DID received signal  480  is set, causing E &amp; M control circuit  450  to force the M-Lead active, thereby seizing the trunk. Control then passes through a connection point labelled “CPF VIRTUAL TRANSFER” at reference  1207 . At step  1208  the subscriber master record  700  which corresponds to the received DID number is retrieved from the database of memory  500 . At step  1209  the call count  731  is incremented in the subscriber master record  700 . At step  1210  a check is made to determine if the feature timer is active. This is accomplished by checking the feature timer duration  724 . The feature timer is active if the feature timer duration  724  is non zero. If the feature timer is not active, then control passes to step  1213 . If the feature is active, then another check is made at step  1211  to determine if the feature timer has expired since the last call. This is determined by comparing the feature timer duration  724  with the current time and date maintained by CPU  495 . The feature timer has expired if the feature timer duration  724  does not extend beyond the current time and date. If the feature timer has not expired, then control passes to step  1213 . If the feature timer has expired, then at step  1212  the mode memory  800  specified by the feature timer termination mode  725  is copied to the subscriber master record  800 , and the feature timer duration  724  is cleared to zero. Control then passes to step  1213 . A determination is made at step  1213  as to whether the weekly schedule is active by checking the status of the weekly schedule active flag  728 . If the weekly schedule is not active, then control passes to step  1217 . If the weekly schedule is active, then a determination is made a step  1214  as to whether the current step of the weekly schedule is correct. This is accomplished by finding the current step of weekly schedule  726  as pointed to by the weekly schedule current step  727 , and comparing the time and date of the next step with the current time and date. If the current time and date fall between the current step and the next step, then the current step is correct. If, by this process, it is determined that the current step is correct, then control passes to step  1217 . Otherwise, at step  1215 , the weekly schedule current step  727  is incremented to point to the next step. Then at step  1216 , the mode memory number corresponding to the new step of the weekly schedule  726  is found, the corresponding mode memory  800  is copied to the subscriber master record  700 , and then control passes to step  1217 . At step  1217  the status of the dynamic mode assignment flag  730  is checked, and if it is found to be active, control is passed at step  1218  to the CPF—Dynamic Mode Assignment. otherwise, control passes through a connector labelled “CPF MODE” at reference  1219 , and then passes to step  1220 . At step  1220  a determination is made as to whether the current call handling mode  703  is set for ‘direct forwarding’, and if so control is passed via step  1221  to the CPF—Direct forwarding. Otherwise a determination is made at step  1222  as to whether the current call handling mode  703  is set for ‘announced forwarding’ and if not control passes to step  1230 . If the call handling mode  703  is set for ‘announced forwarding’, then at step  1223  a further check is made to determine if the transfer number  707  is set for meet-me, and if not control passes to step  1230 . If the transfer number  707  is set for meet-me, then at step  1224  one audible ring is played to the caller by call processor  435 . Then at step  1225 , the ‘pager display digits’ are set to be equal to the DID number, prior to the “send page” subroutine being called at step  1226 . Upon receiving a page with his own DID number in the display, the subscriber may recognize this as a meet-me call. Then a 4 second delay is initiated at step  1227 , another ring is generated at step  1228 , and another 4 second delay is initiated at step  1229 , before passing control to step  1230 . As can be seen, the effect of steps  1224  to  1229  is to simulate the typical ringing cadence expected by a caller, and in addition allow some time for the page sent at step  1225  to reach the subscriber&#39;s pager. Because the caller must wait for the subscriber to get to a phone when the subscriber is using meet-me, the sequence of steps  1224  to  1229  has the effect of reducing the delay received by the caller. At step  1230 , an audible ring is generated towards the caller by call processor  435 . Then at step  1231  a determination is made as to whether the caller has entered the PIN code  702 . If the PIN code has been entered, then the caller must be the subscriber, and therefore control passes to the CPF—Command Mode via step  1233 . If the PIN code has not been entered, then the control passes to step  1270  where a determination is made as to whether the ‘message center access code’ has been entered by the caller. In the preferred embodiment the ‘message center access code’ consists of the digits “*9” and is the same for all subscribers. This code may be used by callers who simply wish to leave a message and do not need to speak with the subscriber. If the ‘message center access code’ has been entered by the caller, then control passes to the “CPF—Caller Message Center” function as shown at step  1271 . If the ‘message center access code’ has not been entered, then control passes to connector label “CPF GREETING” as shown at reference  1232 . 
     Still referring to FIGS. 12 a  and  12   b , control passes through the connector labelled “CPF GREETING” at reference  1233  to step  1234 , where a determination is made as to whether the call handling mode  703  is set for ‘branch-routing’, and if so control passes through a connector labelled “CPF PIN” at reference  1235 . Otherwise, at step  1236  the standard greeting type  704  is retrieved from the subscriber master record  700 . If the standard greeting type is ‘stock’ as determined at step  1237 , then control passes to step  1238  where a stock generic greeting is played to the caller: “Hello, you have reached your party&#39;s telephone control system.” Control then passes through a connector labelled “IF PIN” at reference  1239 . If the standard greeting type is not determined to be ‘stock’ at step  1237 , then a further check is made at step  1240  to determine if the standard greeting type is ‘drop-in’, and if not the control is passed to step  1245 . If the standard greeting type is ‘drop-in’ then at step  1241  the subscriber&#39;s prerecorded drop-in name is retrieved from disk  505 . Then at step  1242  the call processor  435  plays the greeting: “Hello, you have reach the telephone control system for . . . ”, and then at step  1243  completes the greeting by playing back the pre-recorded name of the subscriber retrieved form disk in step  1241 . Control then passes through a connector labelled “CPF PIN” at  1244 . 
     As was described earlier, if the standard greeting type was found not to be ‘drop-in’ at step  1240  then control passed to step  1245 . At step  1245 , a check is made to determine if the standard greeting type is ‘personalized’, and if not control passes to step  1238 , described earlier. Otherwise, control passes to step  1246  where the subscriber&#39;s pre-recorded personalized greeting is retrieved from disk  505 , and is then played back to the caller at step  1247  by call processor  435 . Control then passes through connector labelled “CPF PIN” at reference  1248  and a check is made at step  1249  to determine if the caller has entered a PIN code. If the PIN code has been entered, then the caller must be the subscriber, and therefore control passes to the CPF—Command Mode via step  1250 . If the PIN code has not been entered, then the control passes to step  1272  where a determination is made as to whether the ‘message center access code’ has been entered by the caller. As was described earlier, in the preferred embodiment the ‘message center access code’ consists of the digits “911” and is the same for all subscribers. This code may be used by callers who simply wish to leave a message and do not need to speak with the subscriber. If the ‘message center access code’ has been entered by the caller, then control passes to the “CPF—Caller Message Center” function as shown at step  1273 . If the ‘message center access code’ has not been entered, then control passes to step  1251 , where the call handling mode  703  is retrieved from the subscriber master record  700 . Then at step  1252  a check is made to determine if the call handling mode  703  is set for ‘announced forwarding’, and if so a further check is made at step  1253  to determine if the transfer number  707  is set for meet-me. If the transfer number is not set for meet-me then control passes to CPF—Announced Forwarding via step  1254 . If the transfer number is set for meet-me, then control passes to CPF—Meet-Me Caller via step  1255 . If at step  1252  it was determined that the call handling mode was not set for ‘announced forwarding’, then control passes to step  1256 . At step  1256  a check is made to determine if the call handling mode  703  is set for ‘urgent screen forwarding’, and if so control passes to CPF—Urgent Screen via step  1257 . Otherwise, at step  1258  a check is made to determine if the call handling mode  703  is set for ‘VIP code screen forwarding’, and if so control passes to CPF—VIP Code Screen via step  1259 . Otherwise, at step  1260  a check is made to determine if the call handling mode  703  is set for ‘voice screen forwarding’, and if so control passes to CPE—Voice Screen via step  1261 . Otherwise, at step  1262  a check is made to determine if the call handling mode  703  is set for ‘branch-routing’, and if so control passes to CPF—Branch-Routing via step  1263 . Otherwise control passes to CPF—Message Center via step  1264 . 
     A flowchart of the CPF—Dynamic Mode Assignment is illustrated in FIG.  13 . The purpose of this function is to process calls for a subscriber who is using a Communicator  11 , and who has selected the dynamic mode assignment mode of operation. The dynamic mode assignment mode of operation allows a subscriber to chose dynamically, with each incoming call, the call handling mode to be used for the call. The subscriber is alerted via his Communicator  11  that an incoming call is present, and the subscriber may then transmit a ‘new mode memory’ message from his Communicator  11  thereby informing the Telephone Control System  1  as to how the call should be handled. The CPF—Dynamic Mode Assignment function is entered at step  1300 , and at step  1301  the ‘pager display digits’ are set equal to the communicator dynamic mode display number  718 . At step  1302 , the ‘send page’ subroutine is called, causing a page to be sent to the subscriber&#39;s Communicator  11 . At step  1303 , a ring count is set to a value of  4 . At step  1304  an audible ring is played to the caller by call processor  435 , and at step  1313  a determination is made as to whether the caller has entered the PIN code  702 . If the PIN code has been entered, then the caller must be the subscriber, and therefore control passes to the CPF—Command Mode via step  1314 . If the PIN code has not been entered, then the control passes to step  1315  where a determination is made as to whether the ‘message center access code’ has been entered by the caller. As was described earlier, in the preferred embodiment the ‘message center access code’ consists of the digits “*9” and is the same for all subscribers. This code may be used by callers who simply wish to leave a message and do not need to speak with the subscriber. If the ‘message center access code’ has been entered by the caller, then control passes to the “CPF—Caller Message Center” function as shown at step  1316 . If the ‘message center access code’ has not been entered, then at step  1305  a 4 second delay is initiated, thus creating a typical ring cadence. At step  1306  a check is made to determine if the Network Message Task (FIG. 10) has received a ‘new mode memory’ message from the Communicator  11  belonging to this subscriber. If such a message has been received, then the control passes to connector labelled “CPF MODE” as indicated at reference  1307 . If message was not received, then the ring count is decremented at step  1308 , and at step  1309  a check is made to determine if the ring count is 0. If the ring count is not &#39;0, then control returns to step  1304  and the ring cycle is repeated. If the ring count is 0, indicating four rings cycles have been generated without the subscriber responding, then control passes to step  1310 , labelled “CPF SORRY” by the connector at reference  1311 , and the caller is informed, via call processor  435 : “I&#39;m sorry, your party is not available at the moment. We will connect you to your party&#39;s message center where you may leave a detailed message.” Control then passes to CPF—Caller Message Center via step  1312 . 
     A flowchart of the CPF—Direct Forwarding function is illustrated in FIGS. 14 and 14 a . The purpose of this function is to process calls for a subscriber who has selected the ‘direct forwarding’ call handling mode. In this mode, calls are transferred without any announcement. Low amplitude ‘confidence tones’ are generated just prior to the transfer so that the subscriber may have an opportunity to enter his PIN Code. The CPF—Direct Forwarding function is entered at step  1400 , and ‘confidence tones’ are generated at step  1401  by call processor  435 . The ‘confidence tones’ are a prerecorded sequence of tones which are designed to sound similar to the interoffice multifrequency signalling tones that callers are familiar with. In this way the caller has no clear indication that the call is being answered and transferred, and yet at the same time the subscriber is given indication as to when he may enter his PIN Code. At step  1402 , a determination is made as to whether the subscriber has entered his PIN code. If the PIN code has been entered, then control passes to CPF—Command Mode via step  1403 . Otherwise control passes to step  1416  where a determination is made as to whether the ‘message center access code’ has been entered by the caller. As was described earlier, in the preferred embodiment the ‘message center access code’ consists of the digits “*9” and is the same for all subscribers. This code may be used by callers who simply wish to leave a message and do not need to speak with the subscriber. If the ‘message center access code’ has been entered by the caller, then control passes to the “CPF—Caller Message Center” function as shown at step  1417 . If the ‘message center access code’ has not been entered, then control passes to a connector labelled “CPF DIAL TRANSFER” at reference  1404  to step  1405 , where a check is made to determine if the transfer number  707  contains a reference to a reserved phone number (a tag) or a reference to a mode memory. Tags may be used as follows: 
     
       
         
               
               
             
           
               
                   
               
               
                 TAG DIGIT 
                 RESERVED PHONE NUMBER 
               
               
                   
               
             
             
               
                 1 
                 message center number 709 
               
               
                 2 
                 pager number 710 
               
               
                 3 
                 office number 711 
               
               
                 4 
                 home number 712 
               
               
                 5 
                 mobile phone number 713 
               
               
                 6 
                 meet-me tag 
               
               
                 7 
                 ‘externally entered’ number 
               
               
                   
               
             
          
         
       
     
     As will be described in more detail later in this discussion, if a mode memory  800  has a transfer number  707  that is an ‘externally entered’ number tag, then when that mode memory is invoked, the transfer number is not changed from the previous value. Also, if a mode memory which contains a transfer number  707  that is an ‘externally entered’ number tag can be invoked remotely by the subscriber via a Feature Group D trunk, causing the ANI number received by the trunk to be used as the transfer number  707 . The reference to the mode memory may be in the form of the two digit mode memory number 10-99. Therefore, at step  1405 , if the transfer number  707  contains the digits 1 through 6, or the digits 10 through 99, then control will pass to step  1406 . Otherwise, control will pass to step  1409 . At step  1406  a determination is made as to whether the transfer number  707  contains the meet-me tag (ie. digit 6). If the meet-me tag is found, then control passes to the CPF—Meet-Me caller Function via step  1407 . If the meet-me tag is not found at step  1406 , then control passes to step  1408 , where the tag or mode memory is expanded to a real phone number which can be dialed. If the transfer number  707  contains a tag, then the corresponding reserved phone number per the table above is used as the expanded number to be dialed. If the transfer number  707  contained a mode memory number, then the transfer number  707  from the corresponding mode memory  800  is used as the expanded number to be dialed. Control then passes to step  1409 , where a determination is made as to whether the transfer number to be dialed can be found as the ACCESS NUMBER 801 in any of the subscriber master records  700 . If so, then it is not necessary to do a physical transfer, and the call can be continued on the same trunk by passing control through the connector labelled “CPF-VIRTUAL TRANSFER” at reference  1410 . Otherwise, at step  1411  a flash is generated by call processor  435  by producing a 700 millisecond on hook signal on the on/off hook control line  485 . This flash places the calling party on hold and causes a second dial tone to be returned on trunk  3  by the serving central office of the PSTN  2 . At step  1412  a brief pause is introduced to allow time for the dial tone to appear on the trunk, and then at step  1413  the transfer number is dialed via the DTMF generator of call processor  435 . Then at step  1418  the ‘busy/no-answer’ option flag of options  705  of subscriber master record  700  is checked. The function of this option is to handle calls which are being sent to a subscriber even if the subscriber&#39;s line is busy or does not answer. If this option is active then at step  1419  a flash is generated by call processor  435  causing the calling party to be taken off hold and connected to the call being placed to the transfer number. The calling party will thus be able to hear the progress of the call and will therefore hear the subscriber answer if the subscriber does indeed answer. At step  1420  a determination is made as to whether the call was local or long distance. If the transfer number was longer than 7 digits, or if the 7 digit number contained a prefix which is long distance in this area, then the call was long distance and a 40 second timer is started at step  1422 . If the transfer number was less than or equal to 7 digits, then the call was local and a 25 second timer is started at step  1421 . Then at step  1423  a determination is made as to whether precision busy/ring detector  437  is detecting busy signal, and if not control passes to step  1424 . If a busy signal is detected at step  1423 , indicating that the subscriber&#39;s line is busy, then control passes to step  1429  where a flash is generated by call processor  435  causing the call attempt to be dropped but leaving the calling party connected to the telephone control system  1 . Control then passes to a connector labelled “CPF—Sorry” as shown at step  1430 , which causes the caller to be sent to the subscriber&#39;s message center function. If at step  1423  a busy signal was not detected, then control passes to step  1424  where a determination is made as to whether the timer has expired. If the timer has expired, indicating that neither busy or ringing where detected, then control passes to  1414 . If at step  1424  it is determined that the timer has not expired, then control passes to step  1425  where a determination is made as to whether precision busy/ring detector  437  is detecting a first ringing signal, and if not control returns to step  1423 . If the first ringing signal is detected at step  1426 , then control passes to step  1426 , where a determination is made as to whether this is the fourth ring signal, and if so, indicating that the subscriber is not answering the call, then control passes to step  1429  causing the caller to be ultimately routed to the subscriber&#39;s message center function as was described earlier. If at step  1426  it is determined that this is not the fourth ring, then control passes to step  1427  where control idles until an end-of-ring is detected by precision busy/ring detector  437 . Control then passes to step  1428  where a 6 second ‘inter-ring timer’ is started. Control then passes to step  1431  where a determination is made as to whether precision busy/ring detector  437  is detecting ringing signal and if so control returns to step  1426 . If however at step  1431  it is determined that ringing signal is not being detected, then control passes to step  1432  where the ‘inter-ring timer’ is checked. If the ‘inter-ring timer’ has not expired then control returns to step  1431 . If the ‘inter-ring timer’ has expired, indicating the subscriber has answered the call, then control passes to step  1414 . At step  1414  an on hook signal is generated on the on/off hook control line  485 , causing the call to be transferred to the dialed number, and freing up the trunk  3  to handle another incoming call. Control then passes to the connector labelled “CPF IDLE” at reference  1415 . 
     A flowchart of the CPF—Announced Forwarding function is illustrated in FIGS. 15 a  and  15   b . The purpose of this function is to process calls for a subscriber who has selected the ‘announced forwarding’ call handling mode. In this mode, callers are greeted with a brief courtesy announcement prior to being transferred. In addition, if a ‘page option’ has been selected, then a page is sent to the subscriber&#39;s pager prior to transferring the call. The CPF—Announced Forwarding function is entered at step  1500  and at step  1501 , a determination is made as to whether the page flag of options  705  is set, and if it is not set, then control passes to the connector labelled “CPF AF2” at reference  1502 . If the page flag is set, the control passes to step  1503  where the display digits are set equal to the pager forwarding display number  717 . At step  1504  the ‘send page’ subroutine is called causing a page to be sent to the subscriber&#39;s pager. Then at step  1505 , the call processor  435  plays to the caller the message: “We are sending a page to inform your party of your call. Please stay on the line.” At step  1506  a delay is initiated to allow the pager sufficient time to receive the page. Then at step  1507 , another message is played to the subscriber: “We have sent a page to your party and we will connect your call momentarily. Please stay on the line.” At step  1508  an additional delay is initiated to allow the subscriber the opportunity to get to a phone. Control then passes to the connector labelled “CPF AF2” at reference  1509 . The connector labelled “CPF AF2” at reference  1510  passes control to step  1511 , where the transfer message type ‘0’ is retrieved from subscriber master record  700 . Then at step  1512 , a check is made as to whether the transfer message type is ‘0’. If the transfer message type is ‘0’, indicating no transfer message is to be played, then control passes to the connector labelled “CPF DIAL TRANSFER” at reference  1520 . If the transfer message type is not ‘0’, then control passes to step  1513  where a check is made to determine if the transfer message type is ‘1’. If the transfer message type is ‘1’, then at step  1514  the call processor  435  plays to the caller the message: “We&#39;re connecting your call”, and then control passes to the connector labelled “CPF DIAL TRANSFER” at reference  1520 . If the transfer message type is not ‘1’, then control passes to step  1515  where a check is made to determine if the transfer message type is ‘2’. If the transfer message type is ‘2’, then at step  1516  the call processor  435  plays to the caller the message: “We&#39;re connecting your call. When the call is answered, please ask for your party by name”, and then control passes to the connector labelled “CPF DIAL TRANSFER” at reference  1520 . If the transfer message type is not ‘2’, then control passes to step  1517  where a check is made to determine if the transfer message type is ‘3’. If the transfer message type is ‘3’, then at step  1518  the call processor  435  plays to the caller the message: “We&#39;re connecting your call. When the call is answered, please ask for extension number . . . ” Then at step  1519 , the extension number  708  is retrieved from the subscriber master record  700  and is voiced to the caller by call processor  435 . Control then passes to the connector labelled “CPF DIAL TRANSFER” at reference  1520 . 
     A flowchart of the CPF—Urgent Screen function is illustrated in FIG.  16 . The purpose of this function is to process calls for a subscriber who has selected the “priority screen” or ‘urgent screen’ call handling mode. The CPF—Priority/Urgent Screen function is entered at step  1600 , and control passes to step  1601 , where call processor  435  plays to the caller the message: “Your party is not readily available at the moment. If this call is . . . .” Control then passes to step  1602  where the urgent/emergency flag of the options  705  is checked. If the flag is set for ‘urgent’, then the call processor  435  plays to the caller “. . . urgent . . . ”, and if the flag is set for emergency then call processor  435  plays to the caller “. . . an emergency . . . .” Control then passes to step  1603  where the call processor completes the sentence by playing the message “. . . then touch 0 now and we will attempt to connect your call. Otherwise, we will connect you to your party&#39;s message center where you may leave a detailed message.” Then at step  1604 , a 5 second timer is started. At step  1605  a determination is made as to whether the caller has touched 0. If the caller has touched 0, then control passes to the CPF—Announced Forwarding function via step  1606 . If the caller has not touched 0, then at step  1607  a determination is made as to whether the 5 second timer has expired. If the 5 second timer has not expired then control returns to step  1605 . If the 5 second timer has expired, then at step  1608  the caller is informed: “Please standby”. Control then passes to the CPF—Caller Message Center function via step  1609 . 
     A flowchart of the CPF—VIP Code Screen function is illustrated in FIG.  17 . The purpose of this function is to process calls for a subscriber who has selected the ‘VIP code screen’ call handling mode. The CPF—VIP Code Screen function is entered at step  1700  and control is passed to step  1701  where the call processor  435  plays to the caller the message: “Your party is not readily available at the moment. Please enter your code now, or we will connect you to your party&#39;s message center where you may leave a detailed message.”Control then passes to step  1702  where a 5 second timer is started. At step  1703  a determination is made as to whether the caller has entered the VIP screen code  714  as stored in the subscriber master record  700 . If the caller has entered the correct VIP screen code, then control passes to the CPF—Announced Forwarding function via step  1704 . If the caller has not entered the VIP screen code  714 , then at step  1705  a determination is made as to whether the 5 second timer has expired. If the 5 second timer has not expired then control returns to step  1703 . If the 5 second timer has expired, then at step  1706  the caller is informed: “Please standby”. Control then passes to the CPF—Caller Message Center function via step  1707 . 
     A flowchart of the CPF—Branch Routing function is illustrated in FIG.  18 . The purpose of this function is to process calls for a subscriber who has selected the ‘branch-routing’ call handling mode. The CPF—Branch Routing function is entered at step  1800 , and control passes to step  1801  where the prerecorded branch-routing greeting is retrieved from disk  505 . Then at step  1802 , the playback to the caller of the branch-routing greeting is begun by call processor  435 . At step  1803  a determination is made as to whether the caller has entered a digit. If the caller has not entered a digit then at step  1804  a determination is made as to whether the call processor  435  has completed the playback of the branch-routing greeting, and if an additional 5 seconds have expired. If this is the case then control passes to step  1805 . If this is not the case, then control returns to step  1803 . If at step  1803  it is determined that the caller has entered a digit, then control passes to step  1806  where a determination is made as to whether there exists a branch-routing number  722  in the subscriber master record  700  which corresponds to the digit entered by the caller. For example, if the subscriber entered digit 4, then a determination is made as to whether the subscriber master record holds a phone number entry in the branch routing number 4 position at  722 . If an entry is found in such a manner, then control passes to step  1807 . Otherwise, control passes to step  1805  where a the branch routing default number  723  is retrieved for the subscriber master record  700 , and is set up to be used as the transfer number for this call. Control then passes to the connector labelled “CPF DIAL TRANSFER” at reference  1808 . Should the caller have entered a digit which corresponded to a branch routing number  722 , then at step  1807  the corresponding branch routing number  722  is retrieved form the subscriber master record  700 , and is setup to be used as the transfer number for this call. Control then passes to the connector labelled “CPF DIAL TRANSFER” at reference  1808 . 
     A flowchart of the CPF—Caller Message Center function is illustrated in FIG.  19 . The purpose of this function is to process calls for a subscriber who has selected the ‘message center’ call handling mode. The CPF—Caller Message Center function is entered at step  1900  and control passes to step  1901  where a determination is made as to whether an external message center has been selected. This determination is made by examining the message center number  709  in the subscriber master record  700 . If the message center number  709  contains a phone number, then external has been selected. If the message center number  709  does not contain a phone number, then internal message center has been selected. The subscriber may chose an external voice mail system, an answering service, his secretary, or any other appropriate phone number for the external message center number  709 . If, at step  1901 , it is determined that the subscriber has selected the internal message center, then control passes to step  1902 , where the caller is prompted: “Please leave your message at the tone . . . BEEP.” Then at step  1903  the callers message is recorded by call processor  435  and stored on disk  505 . At step  1904  a determination is made as to whether the caller has completed leaving the message. This is accomplished by call processor  435  determining if there has been at least 3 seconds of silence on the line since the last sound. If the caller has not completed leaving a message then the recording continues at step  1903 . If the caller has completed leaving a message, then control passes to step  1905 , where the caller is prompted: “Thank you for calling. Good-bye.” Then at step  1906  the trunk is placed on hook by call processor  435  via on/off hook control signal  485 . Control then passes to step  1907 , where a decision is made as to whether a message was actually left. A message is determined to be left if at least 3 seconds of non-silence has been recorded, as determined by call processor  435 . If a message was not left, then control passes to connector labelled “CPF IDLE” at reference  1908 . If a message was left by the caller, then control passes to step  1909 , where the ‘display digits’ are set equal to the pager message center display number. The ‘send page’ subroutine is then called at step  1910 , and control passes to a connector labelled “CPF IDLE” at reference  1911 . Returning now to step  1901 , if a determination is made, in the manner described above, that an external message center is selected, then control passes to step  1912  where the party is informed by call processor  435 : “Please standby,” then control passes to step  193  where a flash is generated by call processor  435  by producing a 700 millisecond on hook signal on the on/off hook control line  485 . This flash places the calling party on hold and causes a second dial tone to be returned on trunk  3  by the serving central office of the PSTN  2 . At step  1914  a brief pause is introduced to allow time for the dial tone to appear on the trunk, and then at step  1915  the message center number  709  is dialed via the DTMF generator of call processor  435 . The message center number may contain special dialing characters, including characters for pausing, waiting for tones, and waiting for answer. Thus a sequence of dialing characters may be constructed to allow the Telephone Control System  1  to transfer calls to a voice mail system requiring the entry of a subscriber ID. For example, an external message center dialing sequence for a typical voice mail system may be: 7 digit phone number of voice mail system+Wait for answer+4 digit voice mail subscriber ID. Continuing now, at step  1916  an on hook signal is generated on the on/off hook control line  485 , causing the call to be transferred to the dialed number, and freeing up the trunk  3  to handle another incoming call. Control then passes to step  1917  where the ‘external message center count’  721  in the subscriber master record  700  is incremented. Control then passes to steps  1909  and  1910  where a page is generated as described above, before returning control to the connector labelled “CPF IDLE” at reference  1911 . 
     A flowchart of the CPF—Voice Screen function is illustrated in FIGS. 20 a ,  20   a - 1 ,  20   b  and  20   c . The purpose of this function is to process calls for a subscriber who has selected the ‘voice screen’ call handling mode. The CPF—Voice Screen function is entered at step  2000  and control passes to step  2001  where the caller is prompted by call processor  435 : “Please state your name and business at the tone. After the tone please stay on the line while we attempt to locate your party and connect your call . . . BEEP.” Control then passes to step  2090  where a determination is made as to whether the caller has entered the ‘VIP screen code’  714 , and if so control passes to the “CPF—Announced Forwarding” function as shown at step  2091 . In this way, a caller who knows the ‘VIP screen code’ is able to be forwarded directly to the subscriber without being voice-screened. If, however, at step  2090  it is determined that the caller has not entered the ‘VIP screen code’  714  then control passes to step  2002  where the caller&#39;s message is recorded by call processor  435  and stored temporarily on disk  505 . At step  2003 , the call processor  435  determines that the caller has completed stating his name and business, by detecting the sound of the voice followed by approximately 3 seconds of silence, at which point the call processor  435  prompts the caller: “Thank you, please standby.” A flash is generated at step  2004 , causing the caller to be placed on hold by the switch  4 , and at step  2005  a pause is initiated to allow time for the switch  4  to provide a dial tone, at which point the transfer number  707  is dialed by the DTMF generator of call processor  435 . At step  2006 , an ‘answer timer’ is started. At step  2007  a determination is made by call processor  435  as to whether the call has been answered. If the call has not been answered, then at step  2008  a decision is made as to whether a time-out or non-answer signal such as a busy, reorder, or operator intercept has been detected by call processor  435 . If so, then control proceeds through a connector labelled “CPF VSCRN FLASH” at reference  2009 , to step  2010 . Otherwise control returns to step  2207 . At step  2010 , a flash is generated, causing switch  4  to temporarily conference the caller through to the non-answer signal, and at step  2011  a 2 second pause is invoked. Then at step  2012  another flash is generated causing switch  4  to drop the conference and restore a simple 2-way connection between the caller and the trunk  3 . Control then passes to a connector labelled “CPF SORRY” at reference  2013 , resulting in the caller being connected to the subscriber&#39;s message center as described earlier in FIG.  13 . Returning the discussion now to step  2007 , if a determination is made that the call is answered, then control passes to step  2014  where the ‘voice screen PIN code hold-off flag’ of options  705  of the master record  700  is checked. If this flag has been set, it means that the subscriber wishes to require that a PIN code be entered by the answering party before the called party&#39;s message is played. This is very useful if the subscriber is having his calls voice-screen forwarded to his office, for example, where the receptionist may answer the call. In this case the receptionist would connect the call to the subscriber and the subscriber would enter his PIN code to hear the calling party&#39;s message before determining whether he wishes to be connected to the calling party. If this flag is set, then control passes to step  2015 , where call processor  435  prompts the answering party: “We are trying to reach . . . .” Then at step  2016 , the subscriber&#39;s prerecorded ‘drop-in’ name is retrieved from disk  505  and played back to the answering party. At step  2017 , the answering party is informed: “Please locate the party or enter your PIN code.” Then at step  2018 , a 5 second delay is introduced, and at step  2019 , a determination is made as to whether the answering party has entered the PIN code  702 . If the PIN code is entered, then control passes to step  2021 . Otherwise, control passes to step  2020 , where a determination is made as to-whether the sequence of steps  2015  through  2020  has been repeated ten times. If not, then control returns to step  2015 , and the sequence is repeated again. However, if this is the tenth repeat, then control passes to the connector labelled “CPF VSCRN FLASH” at reference  2009 , and the calling party is sent to the subscriber&#39;s message center as described earlier. If, at step  2014 , it is determined that the ‘voice screen PIN code hold-off flag’ is not set, or if it is set and the PIN code has been entered as determined at step  2019 , then control passes to step  2021 , where the answering party is informed by call processor  435 : “We have a call holding for . . . ”, and then to step  2022  where the subscriber&#39;s ‘drop-in’ name is retrieved from disk and played. Then at step  2023 , which is identified by the connector labelled “CPF VSCRN LISTEN” at reference  2024 , the caller&#39;s message which was originally recorded at step  2002  is retrieved from disk  505  and played by call processor  435  to the subscriber. Then at step  2025 , which is identified by the connector labelled “CPF VSCRN MENU” at reference  2026 , the subscriber is prompted: “Please touch 1 to connect the call, 2 to send the caller to your message center, 3 to politely send the caller away, 4 to listen to the caller&#39;s message again. 5 to place the caller on hold for 1 minute, 6 to transfer the call elsewhere, or 7 to ask the caller not to call again.” Control then passes through a connector labelled “CPF VSCRN LOOP” at reference  2027 . At reference  2028 , the connector labelled “CPF VSCRN LOOP” passes control to step  2029  where a 10 second timer is started. Then at step  2030 , a determination is made as to whether a digit has been entered by the subscriber, and if so control passes to step  2033 . Otherwise, control passes to step  2031  where the 10 second timer is checked, and if it has not expired control returns to step  2030 . If the timer has expired, then control is passes to the connector labelled “CPF VSCRN FLASH” at reference  2032 , and the caller is connected to the message center as described earlier. If a digit has been entered by the subscriber, then at step  2033 , the digit is checked and if it is not ‘1’, control is passes to step  2043 . If the digit is ‘1’, then control passes to step  2034 , where a flash is generated causing the calling party and the subscriber to be conferenced by switch  4 . Then at step  2035  a determination is made as to whether dial tone is present on the line. If so this would indicate that the conference failed, most likely because the calling party had hung up. If this is the case, then control passes to step  2039 . Otherwise, if dial tone is not detected, then at step  2036 , both the calling party and the subscriber hear call processor  435  play the prompt: “Go ahead please.”, and at step  2037 , the trunk  3  is placed on hook causing the switch  4  to transfer the call allowing the calling party and the subscriber to continue their conversation, while at the same time freeing up trunk  3  to handle another incoming call by passing control back to the CPF—Call Handler Task via the connector labelled “CPF IDLE” at reference  2038 . If the caller had hung up as determined by the detection of dial tone at step  2035 , then at step  2039  another flash is generated to cause switch  4  to take the subscriber off of hold. Then at step  2040 , the subscriber is informed: “I&#39;m sorry, your party has hung up”, and at step  2041  trunk  3  is placed on hook and control is returned to the CPF—Call Handler Task via the connector labelled “CPF IDLE” at reference  2042 . If, as described earlier, at step  2033  it is determined that the digit is not ‘1’, then control is passes to step  2043  where it is determined whether the digit is a ‘2’, and if so control is passes to the connector labelled “CPF VSCRN FLASH” at reference  2044  causing the calling party to be connected to the message center as was described earlier. If the digit is not ‘2’, then control passes to step  2045 , where it is determined if the digit is a ‘3’, and if not control passes to step  2052 . If the digit is a ‘3’, then control passes to step  2046 , where a flash is generated causing switch  4  to temporarily conference the calling party and the subscriber. Then, after a 2 second pause at step  2047 , another flash is generated at step  2048  causing switch  4  to terminate the conference by dropping the subscriber, leaving just the calling party connected to trunk  3 . Then at step  2049 , the calling party is informed by call processor  435 : “I&#39;m sorry, your party is unable to take your call at this time. Thank you for calling. Good-bye.” Then at step  2050 , the trunk  3  is placed on hook thereby disconnecting the calling party and control is returned to the CPF—Call Handler Task via the connector labelled “CPF IDLE” at reference  2051 . If, as described earlier, at step  2045  it is determined that the digit is not ‘3’, then control is passes to step  2052  where it is determined whether the digit is a ‘4’, and if so control is passes to the connector labelled “CPF VCRN LISTEN” at reference  2053 , allowing the subscriber to again hear the calling party&#39;s message as described earlier. If at step  2052  it is determined that the digit is not a ‘4’, then control passes to step  2054  where the digit is checked to determine if it is a ‘5’, and if it is not control passes to a connector labelled “CPF VSCRN DIGIT” at reference  2060 . If the digit is a ‘5, then control passes to step  2055  where a one minute timer in started. Then at step  2056  a determination is made whether any further digits have been entered by the subscriber, and if not control passes to step  2058  where the one minute timer is checked. If the timer is found to have expired, then control passes to a connector labelled “CPF VSCRN MENU” at reference  2059 , causing the menu of step  2025  to be replayed to the subscriber. If the timer is found to have not expired, then control returns to step  2056  where a determination is again made as to whether any digits have been entered by the subscriber, and if so control passes to a connector labelled “CPF VSCRN LOOP” at reference  2057 , thereby allowing the digit to be processed. The connector labelled “CPF VSCRN DIGIT6” at reference  2061  causes control to be passed to step  2062  where a determination is made as to whether the digit pressed by the subscriber is a 6, and if not control passes to step  2075 . If the digit is a ‘6’, then control passes to step  2063  where the subscriber is prompted by call processor  435 : “Please enter the telephone number you wish to have this call transferred to.” Then at step  2064 , the control idles, waiting for a telephone number to be entered by the subscriber. If a phone number is entered, then control passes to step  2065 , where the subscriber is prompted: “Number accepted. Please hang up now.” Then at step  2066  a flash is generated causing switch  4  to temporarily conference the calling party and the subscriber. Then, after a 2 second pause at step  2067 , another flash is generated at step  2068  causing switch  4  to terminate the conference by dropping the subscriber, leaving just the calling party connected to trunk  3 . Then at step  2069  the calling party is prompted by call processor  435 : “Please standby.” Then at step  2070  a flash is generated causing switch  4  to place the calling party on hold and providing a dial tone to the trunk  3 . Then, after a pause for dial tone at step  2071 , the phone number detected in step  2064  is dialed at step  2072 , and at step  2073  trunk  3  is placed on hook causing switch  4  to transfer the calling party to the phone number dialed, and control is returned to the CPF—Call Handler Task via the connector labelled “CPF IDLE” at reference  2074 . If, as described earlier, at step  2062  it is determined that the digit entered by the subscriber is not a ‘6’, then control passes to step  2075 . At step  2075 , a determination is made as to whether the digit is a ‘7’, and if not then control passes to a connector labelled “CPF VSCRN LOOP” at reference  2076  thereby allowing the subscriber to enter another digit. If the digit entered is a ‘7’, as determined at step  2075 , then control passes to step  2077  where a flash is generated causing switch  4  to temporarily conference the calling party and the subscriber. Then, after a 2 second pause at step  2078 , another flash is generated at step  2079  causing switch  4  to terminate the conference by dropping the subscriber, leaving just the calling party connected to trunk  3 . Then at step  2080  the calling party is prompted by call processor  435 : “Your party is not interested in your call. Please remove this party from your list and do not call again. Good-bye.” Then at step  2081  trunk  3  is placed on hook causing switch  4  to disconnect the calling party, and control is returned to the CPF—Call Handler Task via the connector labelled “CPF IDLE” at reference  2082 . 
     A flowchart of the CPF—Meet Me Caller function is illustrated in FIGS. 21 a  and  21   b . The purpose of this function is to process calls for a subscriber why has chosen to have his calls handled by the meet-me function. In the preferred embodiment these calls are handled by conferencing the caller on a trunk  3  of the CPF  100  with a line  120  on the Meet-Me Facility (MMF)  115 . Then when the subscriber calls in to be connected, he is also conference from a trunk  3  of the CPF  100  with a line  120  on the MMF  115 . The CPF may then hang up on both the caller&#39;s trunk  3  and then subscriber&#39;s trunk  3 , thereby transferring the caller and subscriber to the MMF lines  120 . The lines  120  are provisioned with the CENTREX features of ‘call transfer’ and ‘barge-in’, so that the caller and subscriber may then be connected as follows: The line  120  which is connected to the caller dials the CENTREX barge-in command (*77) followed by the CENTREX ‘intercom code’ for the line  120  which is connected to the subscriber. The caller and the subscriber are thus connected, and the line  120  which connects to the subscriber may then go on hook, transferring the subscriber to the caller&#39;s line  120 . The conversation may then take place and only one line of line  120  is used. To fully understand the explanation of the CPF—Meet Me Caller function which follows, it is necessary to also review the explanations which are associated with FIG. 30 (CPF—Command Meet Me), FIG. 33 (MMF block diagram), and FIG. 34 (Meet Me Facility Main Task). Referring now to FIG. 21, the CPF—Meet Me Caller function is entered at step  2100  and control passes to step  2101  where the calling party is informed by call processor  435 : “We are paging your party to a phone. Please stay on the line.” Then at step  2102  a flash is generated causing switch  4  to place the calling party on hold and generate a dial tone on trunk  3 . Then at step  2103  the call processor  435  dials the phone number which is associated with one of the lines  120  which are connected to the Meet-Me Facility (MMF)  115 , and at step  2104  a 15 second timer is initiated. Then at step  2105 , a determination is made as to whether DTMF ‘*’ tone has been detected by call processor  435 , indicating that the MMF  115  has answered. If the ‘*’ tone is not detected, then control passes to step  2106  where the 15 second timer is checked, and if found to have not expired then control returns to step  2105 . If the 15 second timer is found to have expired, then control passes to step  2107 , where a flash is generated causing switch  4  to temporarily conference the calling party to the number dialed above. Then after a 2 second pause at step  2108 , another flash is generated at step  2019 , causing switch  4  to drop the dialed number from the conference, leaving just the calling party connected to trunk  3 . Then at step  2110 , a check is made to determine if dial tone is present on trunk  3 . If dial tone is found to be present, indicating that the sequence of steps  2107  through  2109  had failed to restore the calling party possibly because the conference thought to be created at step  2107  was not allowed by switch  4 , then another flash is generated at step  2111 , which is identified by a connector labelled “CPF MM FLASH” at reference  2134 . This flash causes switch  4  to reconnect the calling party to trunk  3 , and then control passes via a connector labelled “CPF MM MSSG” at reference  2112  to step  2113 . If dial tone is not detected at step  2110 , then control passes directly to step  2113 . At step  2113 , the current time and date is stored in the ‘last meet-me message left’ field  720  of the subscriber master record  700 , and then control passes to the connector labelled “CPF SORRY” at reference  2114 , causing the caller to be connected to the message center as was described earlier. If at step  2105 , the ‘*’ tone is detected, indicating that the MMF  115  has answered, then control passes to step  2115  where call processor  435  dials the digit ‘00’ signifying that this is a caller, not a subscriber. Then at step  2116 , the call processor  435  dials the subscriber&#39;s DID number  701 , to identify to the MMF who the calling party is waiting for. Then at step  2117 , a flash is generated, causing switch  4  to conference the calling party through to this line  120  of the MMF  115 , and at step  2118  a 2 second timer is initiated. Then at step  2119 , a determination is made as to whether another ‘*’ tone is detected by call processor  435 , indicating the conference was successful. If the ‘*’ tone is not detected, this implies that the conference was not successful, most likely because the calling party has hung up. In this case the 2 second timer is checked at step  2120 , and if it is found not to have expired control returns to step  2119 . If the 2 second timer has expired, then control passes via a connector labelled “CPF MM ABANDON” at reference  2121  to step  2122  where the current time and date are stored in the ‘last meet-me abandon’ field  719  of the subscriber master record. Then control passes to step  2123  where the trunk  3  is placed on hook and control is returned to the CPF—Call Handler Task via the connector labelled “CPF IDLE” at reference  2124 . If at step  2119  the ‘*’ tone is detected, then control passes to step  2125  where a repeat count is set to a value of 3. Then at step  2126 , the calling party is informed by call processor  435 : “We have sent a page to alert your party of the call. Your party is currently proceeding to a phone and we will connect you momentarily. If you are unable to wait, you may touch 9 at any time to leave a detailed message which we will relay to your party as soon as they pick up the line.” Then at step  2127 , the call processor  435  plays a ‘music on-hold’ selection of duration 40 seconds. Then at step  2128  a determination is made as to whether the subscriber has called in, by checking the CPF—Call Handler Tasks controlling the other trunks  3  connected to the CPF  100 . If the subscriber is found, and if he has entered his PIN code  702  and touched  4  indicating he wishes to be connected to the caller, then step  2128  will return a positive indication causing control to pass to the connector labelled “CPF MM SUBCALL” at reference  2129 . If a negative indication is returned at step  2128 , then control passes to step  2130  where a determination is made as to whether the caller has entered ‘9’. If the caller does enter ‘9’, then control passes to step  2111 , causing the caller to be connected to the message center as describer earlier. If the caller has not entered ‘9’, then control passes to step  2131 , where a determination is made as to whether the 40 second music-on-hold selection is complete. If it is not complete, then control returns to step  2128 . If the selection is complete, then control passes to step  2132  where the repeat count is decremented. Then at step  2133  a determination is made as to whether the value of the repeat count is now zero. If the value is zero, then control passes to step  2111 , causing the caller to be connected to the message center as describer earlier. If the value of the repeat count is not yet zero, then control returns to step  2127 , where the sequence of steps  2127  through  2133  is repeated once more. The connector labelled “CPF MM SUBCALL” at reference  2135  causes control to be passed to step  2136  where the DTMF fourth column tone digit ‘d’ is dialed by call processor  435  to inform the MMF  115  that the subscriber has arrived. Then at step  2137 , the call processor  435  prompts the calling party: “Your party has picked up the line. One moment and we will connect you.” Then at step  2138 , a 20 second timer is initiated, and at step  2139  the call processor  435  begins to play audible ringing, with a cadence of 2 seconds on, 4 seconds off, to the caller. Then at step  2140 , the 20 second timer is checked, and if it is found to have expired, indicating that the subscriber did not connect to the MMF  115 , then control passes to the connector labelled “CPF MM FLASH” at reference  2141 , causing the caller to be connected to the message center as was described earlier. If the 20 second timer has not expired, then control passes to step  2142  where a determination is made as to whether the subscriber has connected to the MMF  115 , as determined by checking with the CPF—Call Handler Task that was found to be controlling the trunk  3  connected to the subscriber. If the subscriber has not connected to the MMF  115 , then control returns to step  2140 . If the subscriber has connected to the MMF  115 , then the trunk  3  is placed on hook causing switch  4  to transfer the calling party to the line  120  of the MMF  115 , and control is returned to the CPF—Call Handler Task via the connector labelled “CPF IDLE” at reference  2144 . 
     A flowchart of the CPF—Send Page Subroutine is illustrated in FIG.  22 . The purpose of this subroutine is to send page messages via the high speed data network  150  from the CPF  100  to either the PDF  105 , or the CAF  125 . These messages contain the pager number and any digits which are to be transmitted to the display of the pager. The CPF—Send Page Subroutine is entered at step  2200  and control passes to step  2201  where the pager number  710  for this subscriber is retrieved from the subscriber master record  700 . Then at step  2202 , a message is constructed consisting of the pager number  710 , and the display digits which were identified as this subroutine was called. Then at step  2203  a determination is made as to whether the pager number  710  represents a communicator. In the preferred embodiment, each communicator  11  is identified by a pager number  710  which starts with the digits ‘000’. If the pager number  710  is found to be that of a communicator  11 , then control passes to step  2204 , and the data network interface  510  is instructed to send the message via network  150  to the Communicator Access Facility (CAF)  125 , and then control is returned from this subroutine to the calling program, as represented at step  2206 . If the pager number  710  is not found to be that of a communicator  11 , then control passes to step  2205 , where the data network interface  510  is instructed to send the message via network  150  to the Pager Dialing Facility (PDF)  105 , and then control is returned from this subroutine to the calling program, as represented at step  2206 . 
     A flowchart of the CPF—Command Mode function is illustrated in FIGS. 23 a  and  23   b . The CPF—Command Mode function is entered at step  2300  and control passes to step  2301  where the subscriber&#39;s pre-recorded ‘drop-in’ name is retrieved from disk  505 . Then at step  2302 , the call processor  435  prompts the subscriber: “Hello . . . ”, and then plays the back the ‘drop-in’ name. Then at step  2303 , a determination is made as to whether a meet-me call is currently holding for this subscriber. This is determined by checking the CPF—Call Handler Tasks which control the other trunks  3  connected to CPF  100 . If a meet-me call is found to be holding for this subscriber, then at step  2304 , the subscriber is prompted: “A call is holding on your meet-me service. Touch 4 to be connected to the caller.” Control then passes to step  2317 . If a meet-me call is not holding for this subscriber, then control passes to step  2305  where a determination is made as to whether a meet-me caller was recently holding, but hung up without leaving a message. If the time and date stored in the ‘last meet me abandon’ field  719  of the subscriber master record  700  is not more than 20 minutes older than the current date and time, then it is determined that a meet-me caller recently abandoned a call, and control passes to step  2306  where the subscriber is prompted: “A call was recently holding on your meet-me service, however the caller chose not to wait and hung up without leaving a message.” Control then passes to step  2307  where the ‘last meet-me abandon’ field  719  of the subscriber master record  700  is cleared. Control then passes to step  2308 . Control also passes to step  2308  if, at step  2305 , it is determined that a meet-me caller did not recently abandon a call. At step  2308 , a determination is made as to whether a meet-me caller is currently leaving a message for the subscriber. This is determined by checking the CPF—Call Handler Tasks which control the other trunks  3  connected to CPF  100 . If it is determined that a meet-me caller is currently leaving a message for this subscriber, then control passes to step  2309 , where the subscriber is prompted: “A call was recently holding on your meet-me service, however the caller chose not to wait and is currently leaving you a message. When the message is complete we will connect you to your message center, or you may touch * now to skip this.” Control then passes to step  2310  where ‘music-on-hold’ is played to the subscriber by call processor  435 . Control then passes to step  2311  where a determination is made as to whether the meet-me caller has finished leaving the message. If the message is complete, then control passes to the CPF—Command Message Center function as shown at reference  2313 . If the caller is still leaving the message, then control passes to step  2312  where a determination is made as to whether the subscriber has entered the ‘*’ digit. If the ‘*’ digit is not entered, then control returns to step  2311 . If the ‘*’ digit is entered, then control passes to step  2317 . If at step  2308 , a determination is made that a meet-me caller is not currently leaving a message for this subscriber, then control passes to step  2314 , where a determination is made as to whether a meet-me caller recently left a message for this subscriber. If the time and date stored in the ‘last meet me message left’ field  720  of the subscriber master record  700  is not more than 20 minutes older than the current date and time, then it is determined that a meet-me caller recently left a message, and control passes to step  2315  where the subscriber is prompted: “A call was recently holding on your meet-me service, however the caller chose not to wait and instead left you a message.” Control then passes to step  2316  where the ‘last meet-me message left’ field  720  of the subscriber master record  700  is cleared. Control then passes to step  2317 . Control also passes to step  2317  if, at step  2314 , it is determined that a meet-me caller did not recently leave a message. At step  2317 , a determination is made as to whether the subscriber has selected an external message center. As described earlier, this determination is made by examining the message center number  709  in the subscriber master record  700 . If the message center number  709  contains a phone number, then external has been selected. If the message center number  709  does not contain a phone number, then internal message center has been selected. If, at step  2317 , it is determined that the subscriber has selected an external message center, then control passes to step  2318 , where the caller is prompted: “We have transferred . . . ”. Control then passes to step  2319  where the ‘external message center transfer count’  721  is retrieved from the subscriber master record  700 , and is voiced to the subscriber by call processor  435 . Control then passes to step  2320 , where the prompt is completed by playing: “. . . since you last checked messages.” Control then passes to the connector labelled “CPF MODE DESCR” at reference  2323 . If, at step  2317 , it is determined that the subscriber had selected the internal message center, then control passes to step  2321  where the number of messages currently stored for this subscriber on disk  505  is determined. At step  2322  then, the call processor  435  prompts the subscriber: “You have X messages.”, where X is the number determined above. Control then passes to the connector labelled “CPF MODE DESCR” at reference  2323 . The connector labelled “CPF MODE DESCR” at reference  2324 , causes control to be passed to step  2325 , where a description is played of the current call handling mode. This description includes the current mode memory number  715 , the current call handling mode  703 , and the current transfer number  707 , if appropriate. For example, the subscriber may hear: “Your calls are currently being handled by mode memory  10 , urgent-screened forwarding to 555-1111.” If the transfer number  707  is the tag for the subscriber&#39;s home, office, pager, mobile-phone, or message center, then this would be voiced in words, ie: “. . . to your home.” After playing a description of the current call handling mode, then control passes to step  2326 , where a determination is made as to whether the feature timer is currently active. As was described earlier, this determination is made by checking the feature timer duration  724 . If the feature timer is found to be active, then it&#39;s status is voiced to the subscriber at step  2327 . For example, the subscriber may be prompted: “The feature timer is currently active and will cause mode memory  10  to be invoked at 5:30 today.” Control then passes to step  2328 . Control also passes to step  2308  if the feature timer was found to be inactive at step  2326 . At step  2328 , a determination is made as to whether the weekly schedule is active. This determination is made by checking the weekly schedule active flag  728  of the subscriber master record  700 . If the weekly schedule is found to be active, then the status of the weekly schedule is voiced to the subscriber at step  2329 . For example, the subscriber may be prompted: “The weekly schedule is on, and the next step will cause memory  20  to be invoked at 7:30 PM on Tuesday.” Control then passes via connector labelled “CPF MAIN DIRECTORY” at reference  2330  to step  2331 . Control also passes via connector  2330  to step  2331  if the weekly schedule is found to be inactive at step  2328 . At step  2331  the call processor  435  prompts the subscriber: “Main Directory. Enter 1 to check messages, 2 to change your forwarding number, 3 to select a memory, 9 to make a call, or 0 for help.” Control then passes to a loop consisting of steps  2332  through  2339 . At each of these steps a determination is made as to whether a particular digit has been entered by the subscriber. If the result is positive on any of these steps, then control is passed to another function. If the digit ‘1’ is found at step  2332 , then control passes to the CPF—Command Message Center function, as shown at reference  2340 . If the digit ‘2’ is found at step  2333 , then control passes to the CPF—Command Forwarding Number function, as shown at reference  2341 . If the digit ‘3’ is found at step  2334 , then control passes to the CPF—Command Memory function, as shown at reference  2342 . If the digit ‘9’ is found at step  2335 , then control passes to the CPF—Command Outside Call function, as shown at reference  2343 . If the digit ‘0’ is found at step  2336 , then control passes to the CPF—Command Help function, as shown at reference  2344 . If the digit ‘4’ is found at step  2337 , then control passes to the CPF—Command Meet Me function, as shown at reference  2345 . If the digit ‘5’ is found at step  2338 , then control passes to the CPF—Command Branch Route function, as shown at reference  2346 . If the digit ‘8’ is found at step  2339 , then control passes to the CP—Command Advanced features function, as shown at reference  2347 . 
     A flowchart of the CPF—Command Message Center function is illustrated in FIG.  24 . The CPF—Command Message Center function is entered at step  2400  and control passes to step  2401  where a determination is made as to whether the subscriber has selected an external message center. As described earlier, this determination is made by examining the message center number  709  in the subscriber master record  700 . If the message center number  709  contains a phone number, then external has been selected. If the message center number  709  does not contain a phone number, then internal message center has been selected. If, at step  2401 , it is determined that the subscriber has selected an external message center, then control passes to step  2402 , where the caller is prompted: “Please standby.” Control then passes to step  2403  where a flash is generated causing switch  4  to place the subscriber on hold a apply a dial tone to trunk  3 . Then, after pausing for dial tone at step  2404 , the message center number  709  is dialed by call processor  435  at step  2405 . Then at step  2406 , the trunk  3  is placed on hook, causing switch  4  to transfer the subscriber to the message center number. Then at step  2407 , the ‘external message center transfer count’  721  of the subscriber master record  700  is cleared. Control is then returned to the CPF—Call Handler Task via the connector labelled “CPF IDLE” at reference  2408 . If, at step  2401 , it is determined that the subscriber has selected internal message center, then control passes to step  2409 , where a determination is made as to whether the subscriber has any messages stored on disk  505 . If there are no messages stored for this subscriber, then control passes to step  2410 , where the subscriber is informed: “You have no messages.” Then at step  2411 , the subscriber is prompted: “Enter 8 to return to the main directory.” Control then passes to step  2412 , where a determination is made as to whether the digit ‘8’ has been entered, and if it has not been entered, then control returns to step  2410 . If the digit ‘8’ has been entered, then control passes to the connector labelled “CPF MAIN DIRECTORY” at reference  2413 , allowing the subscriber to make additional selections from the main directory of the command mode. If at step  2409 , the determination is made that the subscriber does have messages stored on disk  505 , then control passes to step  2414 , where one of the stored messages is played back to the subscriber, and the subscriber is given the opportunity to save or delete the message by entering the digits ‘1’ or ‘2’ respectively. Control then passes to step  2415 , where a determination is made as to whether the digit ‘9’ has been entered. If the digit ‘9’ is entered, then control passes to the CPF—Command Outside Call function as shown at reference  2416 , where the subscriber is given the opportunity to make a call, perhaps returning a call to the person who left the message. If the digit ‘9’ was not entered, then control passes to step  2417 , where a determination is made as to whether any more messages are stored on the disk  505 . If more messages exist, then control is returned to step  2414 . If no more messages exist, then control passes to step  2418 , where the subscriber is prompted: “You have no more messages. Enter 8 to return to the main directory.” Control then passes to step  2419 , where a determination is made as to whether the digit ‘8’ has been entered, and if it has not been entered, then control returns to step  2418 . If the digit ‘8’ has been entered, then control passes to the connector labelled “CPF MAIN DIRECTORY” at reference  2413 , allowing the subscriber to make addtional selections from the main directory of the command mode. 
     A flowchart of the CPF—Command Forwarding Number function is illustrated in FIG.  25 . The CPF—Command Forwarding Number function is entered at step  2500  and control passes to step  2501  where a determination is made as to whether the current call handling mode  703  for this subscriber is ‘message center’ or branch routing’. Since it is not logical to change a forwarding number in a mode that does not require a forwarding number, if it is determined that either of these modes-are active, then control will pass to step  2502 , where the subscriber will be prompted: “Invalid command.” Control then passes to the connector labelled “CPF MAIN DIRECTORY” at reference  2503 , allowing the subscriber to make additional selections from the main directory of the command mode. If, at step  2501 , it is determined that the current call handling mode  703  is not ‘message center’ or ‘branch routing’, then control passes to step  2504 , where a determination is made as to whether the transfer number  707  is set equal to the ‘meet-me tag’. If so, then control passes to step  2505 , where the subscriber is prompted: “Your calls are currently being forwarded to you via your meet me service.” Control then passes to step  2508 . If, at step  2504 , it is determined that the forwarding number is not equal to the ‘meet-me tag’ then control passes to step  2506 , where the subscriber is prompted: “Your calls are currently being forwarded to . . . ”. Control then passes to step  2507 , where the transfer number  707  is retrieved from the subscriber master record  700 , and voiced to the subscriber. Control then passes to step  2508 , where the subscriber is prompted: “Please enter your new forwarding number, or enter * to skip this, or enter 6 to use your meet-me service.” Control then passes to step  2509 , where a determination is made as to whether the subscriber has entered a valid phone number, or a tag for home, office, or mobile phone. If so, then control passes to step  2510 , where the phone number is stored as the new transfer number  707  in the subscriber master record  700 , and the subscriber is prompted: “Accepted, your calls are currently being forwarded to . . . ”, and the transfer number  707  is voiced. Control then passes to the CPF—Command Feature Timer function as shown at reference  2511 . If it is determined at step  2509  that the subscriber has not entered a phone number, then control passes to step  2512 , where a determination is made as to whether the subscriber has entered the digit ‘6’, and if so control passes to step  2513  where the ‘meet-me tag’ is stored as the transfer number  707  in the subscriber master record  700 , and the subscriber is prompted: “Accepted, your calls are currently being forwarded to you via your meet-me service.”Control then passes to the CPF—Command Feature Timer function as shown at reference  2511 . If it is determined at step  2512  that the digit ‘6’ has not been entered, then control passes to step  2514 , where a determination is made as to whether the digit ‘*’ has been entered, and if not control returns to step  2509 . If the digit ‘*’ has been entered, then the transfer number  707  remains unchanged, and control passes to the CPF—Command Feature Timer function as shown at reference  2511 . 
     A flowchart of the CPF—Command Feature Timer function is illustrated in FIG.  26 . The CPF—Command Feature Timer function is entered at step  2600  and control passes to step  2601  where the subscriber is prompted: “Please enter the length of time you wold like your current feature to be in effect, or enter * to skip the feature timer.” Control then passes to step  2602 , where a determination is made as to whether the digit ‘*’ has been entered by the subscriber. If the digit ‘*’ has been entered, then control passes to step  2603 , where the subscriber is prompted: “Accepted, your feature will be in effect until further notice.” Control then passes to the connector labelled “CPF MAIN DIRECTORY” at reference  2613 , allowing the subscriber to make additional selections from the main directory of the command mode. If at step  2602 , it is determined that the digit ‘*’ has not been entered, then control passes to step  2604  where a determination is made as to whether a valid duration has been entered. This duration must be in the form of hours first followed by minutes. For example, to enter 1 hour and 20 minutes, the subscriber must enter ‘1 2 0’. If a valid duration is not found to be entered at step  2604  then control returns to step  2602 . If a valid duration is entered, then control passes to step  2605 , where the duration is stored as the ‘feature timer duration’  724  of the subscriber master record  700 , and the subscriber is prompted: “Accepted, . . . ” and the duration time is voiced. Control then passes to step  2606  where the subscriber is prompted: “Please enter the memory number you wish to invoke upon termination of the feature timer, or enter * to use the previous mode, or touch 9 to use the schedule.” Control then passes to step  2607 , where a determination is made as to whether the subscriber has entered the digit ‘*’, and if so then at step  2608  the previous mode memory is saved in temporary mode memory  0 , mode memory  0  is stored as the feature timer termination mode  725  of the subscriber master record, and the subscriber is prompted: “Accepted, your feature will be in effect until (time) at which time the previous mode will be invoked.”, where the value of (time) corresponds to the current time plus the feature timer duration  724 . Control then passes to the connector labelled “CPF MAIN DIRECTORY” at reference  2613 , allowing the subscriber to make additional selections from the main directory of the command mode. If at step  2607  it is determined that the digit ‘*’ has not been entered, then control passes to step  2609 , where a determination is made as to whether the digit ‘9’ is entered, and if so control passes to step  2610  where the weekly schedule is saved in temporary mode memory  0 , mode memory  0  is stored as the feature timer termination mode  725  of the subscriber master record, and the subscriber is prompted: “Accepted, your feature will be in effect until (time) at which time the weekly schedule will be invoked.”, where the value of (time) corresponds to the current time plus the feature timer duration  724 . Control passes to the connector labelled “CPF MAIN DIRECTORY” at reference  2613 , allowing the subscriber to make additional selections from the main directory of the command mode. If at step  2609  it is determined that the digit ‘9’ has not been entered, then control passes to step  2611 , where a determination is made as to whether a valid mode memory  10  through  99  is entered, and if so control passes to step  2612  where the mode memory is stored as the feature timer termination mode  725  of the subscriber master record, and the subscriber is prompted: “Accepted, your feature will be in effect until (time) at which time mode memory XX will be invoked.”, where the value of (time) corresponds to the current time plus the feature timer duration  724 . Control passes to the connector labelled “CPF MAIN DIRECTORY” at reference  2613 , allowing the subscriber to make additional selections from the main directory of the command mode. 
     A flowchart of the CPF—Command Memory function is illustrated in FIG.  27 . The CPF—Command Memory function is entered at step  2700  and control passes to step  2701  where the subscriber is prompted: “Your calls are currently being handled via mode memory XX.”, where XX is the current mode memory number  715  of the subscriber master record. Control then passes to step  2702 , where a description of the mode is voiced to the subscriber. This description includes the current call handling mode  703 , and the current transfer number  707 , if appropriate. For example, the subscriber may hear: “Your calls are currently being urgent-screened forwarded to 555-1111.” If the transfer number  707  is the tag for the subscriber&#39;s home, office, pager, mobile-phone, or message center, then this would be voiced in words, ie: “. . . to your home.” Control then passes to step  2703  where the subscriber is prompted: “Please enter a new mode memory number or enter * to skip this.” Control then passes to step  2704  where a determination is made as to whether the digit ‘*’ has been entered. If the digit ‘*’ is entered, then control passes to the CPF—Command Feature Timer function as shown at reference  2722 . If at step  2704 , it is determined that the ‘*’ digit has not been entered, then control passes to step  2705 , where a determination is made as to whether a valid 2 digit mode memory number has been entered, and if such a mode memory number has not been entered, then control returns to step  2703 . If a valid mode memory number is entered, then control passes to step  2706 , where the mode memory number is stored as the current mode memory number  715  of the subscriber master record  700 , the corresponding mode memory  800  is copied to the subscriber master record, the subscriber is prompted: “Accepted, you have selected mode memory XX, which causes your calls to be . . . ”, and then control passes to step  2707 . At step  2707 , the prompt is completed by playing a brief description of the selected mode memory. The description includes the call handling mode  703 , and the transfer number  707  if appropriate. For example, at step  2707  the remainder of the prompt may be: “. . . handled by your message center.” At step  2708  a determination is made as to whether the selected mode memory requires an ‘externally entered number’. This is determined by checking the transfer number field  707  of the selected mode memory, to determine if it contains an ‘externally entered number’ tag. If this is the case, then the subscriber must enter a transfer number after selecting this memory. If the externally entered number is not required, then control passes to the CPF—Command Feature Timer function as shown at reference  2722 . If it is determined at step  2708  that an externally entered number is required, then control passes to step  2710 , where the subscriber is prompted: “Please enter your new forwarding number or enter * to skip this and use . . . ”. Control then passes to step  2711  where the previous transfer number is voiced to the subscriber. Control then proceeds to step  2712  where the subscriber is further prompted with: “. . . or enter  6  to use your meet-me service.” Control then passes to step  2713  where a determination is made as to whether the digit ‘*’ has been entered. If the digit ‘*’ has been entered then control passes to step  2716 . Otherwise, control passes to step  2714  where a determination is made as to whether a phone number or tag has been entered by the subscriber. If not, then control returns to step  2710 . If a phone number or tag has been entered, then control passes to step  2715  where the phone number is stored as the transfer number  707  of the subscriber master record  700 , the subscriber is prompted: “Accepted . . . ”, and the phone number or tag is voiced. Control then passes to step  2716 , where a determination is made as to whether the memory has an extension number in the extension number field  708  of the subscriber master record  700 . If an extension number does not exist in this field, then control passes to the CPF—Command Feature Timer function as shown at reference  2722 . If at step  2716  it is determined that an extension number does exist, then control passes to step  2717  where the subscriber is given an opportunity to modify the extension number. At step  2717  the subscriber is prompted: “Please enter your new extension number or enter * to skip this and use . . . ”. Control then passes to step  2718  where the phrase is completed by voicing the current extension number  708 . Control then passes to step  2719  where a determination is made as to whether a new extension number has been entered, and if so, then control passes to step  2720  where the extension number is stored in the extension number field  708 , the subscriber is prompted: “Accepted, . . . ” the new extension number is voiced, and control passes to the CPF—Command Feature Timer function as shown at reference  2722 . If at step  2719  it is determined that an extension number has not been entered then control passes to step  2721 , where a determination is made as to whether the digit “*” is entered, and if the “*” digit is not entered then control returns to step  2717 . If at step  2721  it is determined that the “*” digit is entered then control passes to the CPF—Command Feature Timer function as shown at reference  2722 . 
     A flowchart of the CPF—Command outside Call function is illustrated in FIG.  28 . The CPF—Command Outside Call function is entered at step  2800  and control passes to step  2801  where the call processor  435  plays a ‘stutter dial tone’ to the subscriber. Control then passes to step  2802  where a determination is made as to whether the subscriber has entered the ‘#’ digit. If the ‘#’ digit has been entered, then control passes to the connector labelled “CPF MAIN DIRECTORY” at reference  2803 , allowing the subscriber to make additional selections from the main directory of the command mode. If at step  2802  it is determined that the subscriber has not entered the ‘#’ digit, then control passes to step  2804  where a determination is made as to whether the subscriber has entered a phone number that he wishes to be connected to. If a phone number has not been entered, then control returns to step  2802 . If at step  2804  it is determined that a phone number has been entered, then control passes to step  2805 , where a flash is generated, causing switch  4  to place the subscriber on hold, and applying a dial tone to the trunk  3 . Then, after a pause for dial tone at step  2806 , the call processor  435  dials the phone number at step  2807 , which had been entered by the subscriber. Control then passes to step  2808 , where the ‘multiple outside calls allowed’ flag  729  of the subscriber master record  700  is checked. If this flag is not active, then control passes to step  2809  where the trunk  3  is placed on hook, causing switch  4  to transfer the subscriber to the dialed number, and control is returned to the CPF—Call Handler Task via the connector labelled “CPF IDLE” at reference  2810 . If at step  2808  it is determined that the ‘multiple outside calls allowed’ flag  729  is set, then control passes to step  2811 , where a flash is generated which causes the subscriber to be conferenced to the dialed number while maintaining trunk  3  in the connection. In this way the subscriber may make additional calls, or later return to the main directory without hanging up and calling back. After the flash is generated at step  2811 , control passes to step  2812  where a loop is entered waiting for the subscriber to enter the digit sequence ‘##’. When trying to detect DTMF digits while conversation may be present, as is the case in this situation, requiring the two digits in sequence reduces the likelihood of falsing on voice. If the subscriber enters ‘##’, then control passes to step  2813  where a flash is generated causing switch  4  to disconnect the third party from the conference, leaving only the subscriber connected to trunk  3 . Control then returns to step  2801 , where the subscriber may make another call, or enter ‘#’ to return to the main directory. 
     A flowchart of the CPF—Command Help function is illustrated in FIG.  29 . The purpose of this function is to provide help to the subscriber who is using the Command Mode features of the Telephone Control System. This is accomplished by allowing the subscriber to enter the digit ‘0’ for help from any of the command mode functions. Once the digit ‘0’ is entered, the subscriber is provided with an explanation of the function which was being accessed at that moment. The subscriber may also touch another digit ‘0’ to reach a live client services representative. The CPF—Command Help function is entered at step  2900  and control passes to step  2901  where the step number of the function from which the CPF—Command Help was requested is saved for later use. Then at step  2902 , the subscriber is prompted: “You have selected the help function. You may enter 0 to be connected to a client services operator, 8 to return to the main directory, or # to return to the point where you were when you entered the help function.” Control then passes to step  2903 , where a context sensitive help prompt is played, based on the step number saved in by step  2901 . For example, if the saved step number indicated that the help function was accessed while in the CPF—Command Forwarding Number function, then the call processor  435  would play the prestored help prompt associated with that function: “When you selected the help function you were in the process of changing your forwarding number.” Control then passes to step  2904  where a determination is made as to whether the digit ‘0’ has been entered, and if so, control then passes to step  2905  where a flash is generated, causing switch  4  to place the subscriber on hold, and applying a dial tone to the trunk  3 . Then, after a pause for dial tone at step  2906 , the call processor  435  dials the phone number at block  2907 , which is associated with a client services representative. Control then passes to step  2908  where the trunk  3  is placed on hook, causing switch  4  to transfer the subscriber to the dialed number, and control is returned to the CPF—Call Handler Task via the connector labelled “CPF IDLE” at reference  2909 . If at step  2904  it is determined that the digit ‘0’ is not entered, then control passes to step  2910  where a determination is made as to whether the digit ‘8’ has been entered, and if so, control passes to the connector labelled “CPF MAIN DIRECTORY” at reference  2911 , allowing the subscriber to make additional selections from the main directory of the command mode. If at step  2910  it is determined that the digit ‘8’ is not entered, then control passes to step  2912  where a determination is made as to whether the digit ‘#’ is entered, and if not control returns to step  2902 . If the digit ‘#’ is entered, then the step number that was saved at step  2901  is retrieved and the control returns to that step. 
     A flowchart of the CPF—Command Meet Me function is illustrated in FIG.  30 . The purpose of this function is to process the call for a subscriber who has called in, entered his PIN code  702 , and wishes to be connected to a meet-me caller who is holding for him. The CPF—Command Meet Me function is entered at step  3000  and control passes to step  3001  where a flash is generated, causing switch  4  to place the subscriber on hold and apply a dial tone to the trunk  3 . Then, after pausing for dial tone at step  3002 , the call processor  435  dials the phone number of the lines  120  which are connected to the Meet Me Facility (MMF)  115  at step  3003 . Control then passes to step  3004  where a 15 second timer is started, and then to step  3005  where the 15 second timer is checked. If the 15 second timer has not expired, then control passes to step  3006  where a determination is made as to whether a ‘*’ digit is detected, indicating that the MMF  115  has answered the call. If the ‘*’ digit is not detected then control returns to step  3005 . If at step  3006 , the ‘*’ digit is detected, then control passes to step  3007  where the call processor  435  dials ‘01’ indicating this call is from a subscriber, and then dials the subscriber&#39;s DID number  701 , thereby fully identifying the call to the MMF  115 . Control then passes to step  3008  where a flash is generated causing switch  4  to take the subscriber off of hold and create a conference between the subscriber, trunk  3 , and the line  120  of the MMF  115 . Control then passes to step  3009  where a  4  second pause is initiated to allow the MMF  115  time to connect the caller into the call. Control then passes to step  3010  where the subscriber and caller are prompted by call processor  435 : “Go ahead please.” Control then passes to step  3011  where the trunk  3  is placed on hook, causing the switch  4  to transfer the subscriber to the line  120  of the MMF  115 . Control is then returned to the CPF—Call Handler Task via the connector labelled “CPF IDLE” at reference  3012 . If at step  3005  it is determined that the 15 second timer had expired, indicating that the MMF  115  had not answered the call, then control passes to step  3013  where a flash is generated causing switch  4  to create a temporary conference between the subscriber and the dialed number, and then after a 2 second pause at step  3014  another flash is generated at step  3015  causing switch  4  to drop the dialed number from the conference and leave just the subscriber connected to the trunk  3 . Control then passes to step  3016  where the subscriber is prompted: “I&#39;m sorry, we are unable to connect your call at this time.” Control then passes to the connector labelled “CPF MAIN DIRECTORY” at reference  3017 , allowing the subscriber to make additional selections from the main directory of the command mode. 
     A flowchart of the CPF—Command Branch Route function is illustrated in FIGS. 31 and 31 a . The CPF—Command Branch Route function is entered at step  3100  and control passes to step  3101  where a determination is made as to whether the current call handling mode  703  is ‘branch-routing’, and if it is not control is passes to step  3102  where the subscriber is prompted: “Invalid command.”, and control passes to the connector labelled “CPF MAIN DIRECTORY” at reference  3103 , allowing the subscriber to make additional selections from the main directory of the command mode. If at step  3101  it is determined that the call handling mode  703  is ‘branch routing’ then control passes to step  3104  where the subscriber is prompted: “Enter 1 to record a new branch routing greeting, 2 to change branch routing numbers, 3 to change the branch routing default number, or ‘#’ to return to the main directory.” Control then passes to step  3105  where a determination is made as to whether the digit ‘1’ is entered, and if so, control passes to step  3106  where the subscriber is prompted: “Your branch routing greeting is . . . ”. Then at step  3107 , the branch routing greeting for this subscriber is retrieved from disk  505  and played back to the subscriber. Control then passes to step  3108  where the subscriber is prompted: “Please record your new branch routing greeting at the tone, or enter * to skip this and use the existing branch routing greeting . . . BEEP.” Then at step  3109 , the new greeting is recorded and control passes to step  3110  where a determination is made as to whether the greeting is done, and if it is control passes to step  3111  where the new branch routing greeting is saved to disk  505  and then control returns to step  3104 . If at step  3110  it is determined that the greeting is not done, then control passes to step  3112  where a determination is made as to whether the digit ‘*’ is entered, and if not control returns to step  3109 . If at step  3112  it is determined that the digit ‘*’ is entered, then control passes to step  3113  where the old branch routing greeting on disk  505  is left unchanged, and control then passes to step  3104 . If at step  3105  it is determined that the digit ‘1’ is not pressed, then control passes to step  3114  where a determination is made as to whether the digit ‘2’ is entered, and if it is entered then control passes to step  3115  where the subscriber is prompted: “Please enter the branch routing directory digit 1 to 9 for the phone number your wish to change, or touch * to skip this.” Control then passes to step  3116  where a determination is made as to whether the digit ‘*’ is entered, and if it is entered control returns to step  3104 . If at step  3116  it is determined that the digit ‘*’ is not entered, then control passes to step  3117  where a determination is made as to whether one of the digits ‘1’ to ‘9’ are entered, and if one of those digits is entered control then passes to step  3118 . Otherwise control returns to step  3116 . At step  3118  the subscriber is prompted: “The branch routing transfer number for digit X is . . . ”. Control then passes to step  3119  where the branch routing number  722  that corresponds to the digit entered in step  3117  is retrieved from the subscriber master record  700  and voiced to the subscriber. Then at step  3120  the subscriber is prompted: “Please enter the new branch routing transfer number or touch * to skip this without making a change.” Control then passes to step  3121  where a determination is made as to whether the digit ‘*’ is entered, and if it is entered control returns to step  3104 . If at step  3121  it is determined that the digit ‘*’ is not entered, then control passes to step  3122  where a determination is made as to whether a phone number has been entered, and if a phone number has not been entered, control returns to step  3121 . If at step  3122  a phone number is entered, then control passes to step  3123  where the subscriber is prompted: “Accepted.” Then at step  3124  the new phone number is voiced to the subscriber. Control then passes to step  3125  where the new phone number is saved as the branch routing number  722  which corresponds to the digit entered in step  3117 . Control then returns to step  3104 . If at step  3114  it is determined that the digit ‘2’ is not entered, then control passes to step  3126  where a determination is made as to whether the digit ‘3’ is entered, and if it is entered, then control passes to step  3127  where the subscriber is prompted: “The branch routing default transfer number is . . . .” Control then passes to step  3128  where the branch routing default number  723  is retrieved from the subscriber master record  700  and voiced to the subscriber. Then at step  3129  the subscriber is prompted: “Please enter the new branch routing default transfer number, or touch * to skip this without making a change.” Control then passes to step  3130  where a determination is made as to whether the digit ‘*’ is entered, and if the digit ‘*’ is entered control returns to step  3104 . If at step  3130  it is determined that the digit ‘*’ is not entered, then control passes to step  3131  where a determination is made as to whether a phone number has been entered, and if a phone number has not been entered control returns to step  3130 . If it is determined at step  3131  that a phone number has been entered, then control passes to step  3132  where the subscriber is prompted: “Accepted.” Control then passes to step  3133  where the new phone number is voiced to the subscriber. Control then passes to step  3134  where the new phone number is saved as the branch routing default number  723  in the subscriber master record. Control then returns to step  3104 . If at step  3126  it is determined that the digit ‘3’ is not entered, then control passes to step  3135  where a determination is made as to whether the digit ‘#’ is entered, and if it is not entered control then returns to step  3104 . at step  3135  it is determined that the digit ‘#’ is entered then control passes to the connector labelled “CPF MAIN DIRECTORY” at reference  3136 , allowing the subscriber to make additional selections from the main directory of the command mode. 
     A flowchart of the CPF—Command Advanced Features function is illustrated in FIG.  32 . The purpose of this function is provide the subscriber with the opportunity to modify those features of the Telephone Control System  1  which do not need to be modified on a regular basis. These features include allowing the subscriber to program mode memories, allowing the subscriber to record his ‘drop-in’ name, or his personalized greeting, allowing the subscriber to program his reserved numbers, and allowing the subscriber to activate or deactivate the weekly schedule. The CPF—Command Advanced Features function is entered at step  3200  and control passes to step  3201  where the subscriber is prompted: “Advanced Features Directory. Enter 1 to program mode memories, 2 to record greetings, 3 to program reserved numbers, 4 to activate the weekly schedule, 5 to deactivate the weekly schedule, or # to return to the Main Directory.” Control then passes to step  3202  where a determination is made as to whether the digit ‘1’ is entered. If the digit ‘1’ is entered, then control passes to step  3203  where the subscriber is allowed to specify a mode memory number  802  of value ‘10 to ‘99’. If the mode memory number  802  specified already exists the call processor voices the status of that memory. The subscriber is then given an opportunity to modify the parameters  803  contained in the mode memory. When the subscriber is finished modifying the contents, the changes are saved in mode memory  800 . Control then returns to step  3201 . If at step  3202  it is determined that the digit ‘1’ is not entered, then control passes to step  3204  where a determination is made as to whether the digit  2  is entered. If the digit ‘2’ is entered, then control passes to step  3205  where the subscriber is allowed to listen to and re-record the ‘drop-in’ name and the ‘personalized greeting’. If the subscriber does re-record either of these, then the changed name or greeting is saved on disk  505 . Control then returns to step  3201 . If at step  3204  it is determined that the digit ‘2’ is not entered, then control passes to step  3206  where a determination is made as to whether the digit ‘3’ is entered. If the digit ‘3’ is entered, then control passes to step  3207  where the subscriber is allowed to modify the ‘message center number’  709 , the ‘pager number’  710 , the ‘office number’  711 , the ‘home number’  712 , or the ‘mobile phone number’  713 . If the subscriber changes any of these numbers then the new number is saved in the corresponding field of the subscriber master record  700 . Control then returns to step  3201 . If at step  3206  it is determined that the digit ‘3’ is not entered, then control passes to step  3208  where a determination is made as to whether the digit ‘4’ is entered. If the digit ‘4’ is entered, then control passes to step  3209  where the subscriber is allowed to activate the weekly schedule. If the subscriber chooses to activate the weekly schedule, then the ‘weekly schedule active’ flag  728  of the subscriber master record  700  is set. Control then returns to step  3201 . If at step  3208  it is determined that the digit ‘4’ is not entered, then control passes to step  3210  where a determination is made as to whether the digit ‘5’ is entered. If the digit ‘5’ is entered, then control passes to step  3211  where the subscriber is allowed to deactivate the weekly schedule. If the subscriber chooses to deactivate the weekly schedule, then the ‘weekly schedule active’ flag  728  of the subscriber master record  700  is cleared. Control then returns to step  3201 . If at step  3210  it is determined that the digit ‘5’ is not entered, then control passes to step  3212  where a determination is made as to whether the digit ‘#’ is entered. It the digit ‘#’ is not entered, then control returns to step  3201 . If at step  3212  it is determined that the digit ‘#’ is entered then control passes to the connector labelled “CPF MAIN DIRECTORY” at reference  3213 , allowing the subscriber to make additional selections from the main directory of the command mode. 
     A block diagram of the Meet-Me Facility (MMF)  115  is illustrated in FIG.  33 . As was discussed earlier, the MMF  115  interfaces to tip-ring lines  120 . These lines are provisioned by switch  4  with the CENTREX feature of ‘call transfer’, which allows a caller to be transferred to another number by flashing, dialing the number, and then going on hook. These lines are also provisioned by switch  4  with the CENTREX feature of ‘barge-in’, which allows a party on one of the lines  120  to barge into a conversation in progress on another of the lines  120 . This is accomplished by flashing, dialing a barge-in code (*77), and then dialing the intercom code associated with the line  120  of the conversation to be barged-in on. As was mentioned earlier, to fully understand the operation of the meet-me feature it is necessary to also review the explanations which are associated with FIG. 21 (CPF—Meet Me Caller), FIG. 30 (CPF—Command Meet Me), and FIG. 34 (Meet Me Facility Main Task). Referring now to FIG. 33, the lines  120  are shown connected to call processors  3300 , which contain a tip-ring interface and DTMF generators and detectors. The functions of call processor  3300  are well known in the art, and many products, such as the Model D41B manufactured by Dialogic Corporation, exist commercially which can accomplish these functions. The MMF  115  also contains a CPU  3301  which contains among other things a microprocessor, a boot ROM, a RAM, and a disk. The MMF  115  also contains a data network interface module  3302  which connects to the high speed data network  150 . The functions of data network interface  150  are well known in the art, and many products, such as the Model COM4i from Digiboard Corporation, exist commercially which can accomplish these functions. The call processors  3300 , the CPU  3301 , and the data network interface  3302  are all shown connected to an internal data bus  3303 . The CPU  3301  initializes itself at power-up using the boot ROM and then loads a control program into memory which it then executes. The control program allows for the control of simultaneous activities on the lines  120 . 
     A flowchart of the Meet Me Facility Main Task is illustrated in FIG.  34 . The Meet Me Facility Main Task is the part of the MMF  115  control program which controls the activities on one of the lines  120 . The Meet Me Facility Main Task is entered at step  3400  and control passes to step  3401  where a determination is made as to whether the call processor  3300  has detected a ring signal on the line  120 , and if a ring signal is not detected, then control remains at step  3401 . If a ring signal is detected, then control passes to step  3402 , where the line  120  is taken off hook by call processor  3300 , thereby answering the incoming call. At step  3403 , a 1 second pause is initiated to allow for the line  120  to settle, and then at step  3404  the call processor  3300  dials the DTMF digit ‘*’ as an answer indication to the CPF  100  which is calling. Then at step  3405  a 5 second timer is started, and control then passes to step  3406  where the 5 second timer is checked. If the 5 second timer has expired, then control passes to step  3407  where the line  120  is placed on-hook by call processor  3300 , and then control returns to step  3401 . If at step  3406  it is determined that the 5 second timer has not expired, then control passes to step  3408  where a determination is made as to whether the DTMF digit sequence ‘00’ is detected by call processor  3300 , indicating the call is a meet-me caller from CPF  100 . If the digit sequence ‘00’ is not detected, then control passes to step  3409  where a determination is made as to whether the DTMF digit sequence ‘01’ is detected, indicating the call is a meet-me subscriber from CPF  100 . If the digit sequence ‘01’ is not detected, then control returns to step  3406  where the 5 second timer is again checked. If at step  3408  it is determined that the digit sequence ‘00’ is detected, then control passes via a connector labelled “MMF CALLER” at reference  3410  to step  3411 , where a determination is made as to whether a DTMF digit sequence representing the Access Number  701  of the subscriber being called is detected by call processor  3300 . If a valid phone number is not detected, then control remains at step  3411 . If a valid phone number is detected, then control passes to step  3412  where a 2 second pause is initiated. Then at step  3413 , the call processor  3300  dials the DTMF digit ‘*’ to inform the CPF  100  that the connection has been successful so far. Control then passes to step  3414  where a determination is made as to whether the DTMF digit ‘d’ is detected, indicating that the subscriber has called into the CPF  100 , and the CPF  100  is about to conference him to the MMF  115 . If the digit ‘d’ is not detected then control remains at step  3414 . If the digit ‘d’ is detected, then control passes to step  3415  where a flash is generated on lines  120  causing the CENTREX system serving lines  120  to place the calling party (in this case the CPF  100 ) on hold, and a dial tone to be applied to line  120 . Control then passes to step  3416  where a determination is made as to whether the subscriber has yet been connected to one of the other of lines  120  on the MMF  115 . If the subscriber has not yet been connected, then control remains at step  3416 . If it is determined that the subscriber has connected to one of the other of lines  120 , then control passes to step  3417 , where the CENTREX ‘barge-in code’ (*77) is dialed by the DTMF generator of call processor  3300 . Then at step  3418 , the call processor  3300  dials the intercom code for the line  120  which is currently connected to the subscriber. Control then passes to step  3419  where a 2 second pause is generated, and then to step  3420  where a flash is generated. This causes the line  120  which is connected to the subscriber to be connected via the CENTREX system to the line  120  which is connected to the caller. Control then passes to step  3421  where control remains while the subscriber and caller converse, until a loop interruption signal is detected on line  120  indicating at least one of the two parties has disconnected. Control then passes to step  3422  where the line  120  is placed on hook, and control the returns to step  3401 . If at step  3409  it is determined that the digit sequence ‘01’ is detected, then control passes via a connector labelled “MMF SUBSCRIBER” at reference  3423  to step  3424 , where a determination is made as to whether a DTMF digit sequence representing the Access Number  701  of the subscriber is detected by call processor  3300 . If a valid phone number is not detected, then control remains at step  3424 . If a valid phone number is detected, then control passes to step  3425  where an indication is made available that a subscriber is connected to the MMF  115  on this line  120 . Control then passes to step  3426  where a 3 second pause is initiated, allowing time for the line  120  connected to the subscriber to perform the barge-in sequence. Control then passes to step  3427  where the line  120  is placed on hook causing the CENTREX system to call transfer the subscriber to the line  120  which has just barged-in. Control then returns to step  3401 . 
     A block diagram of the Subscriber Access Facility (SAF)  110  is illustrated in FIG.  35 . The SAF  110  provides a means by which subscribers can access the Telephone Control System  1  via trunks which provide automatic number identification (ANI). SAF trunk interface  3500  interfaces the SAF  110  with trunks  8 . The trunk interface  3500  is the same trunk interface as was described earlier at reference  400  used in the CPF  100 , however the E &amp; M Lead Control Circuit operates under a slightly different set of instructions, as will be described below in the explanation which accompanies FIG.  36 . Still referring to FIG. 35, as was discussed earlier, the preferred embodiment of the TELEPHONE CONTROL SYSTEM  1  employs a Feature Group D (FGD) facility for trunks  8 . This is provided via a 4-wire E&amp;M trunk provisioned with TYPE I signaling, which is well known in the art. These type of trunks provide a 2-wire balanced transmit audio connection, a 2-wire balanced receive audio connection, an E-Lead, and an M-Lead. Although only one trunk interface  3500 , one trunk  8 , and one call processor  3504  are shown in FIG. 35, it should be readily evident to one skilled in the art that additional trunk interfaces and call processors may be added to support additional trunks. The trunk interface  3500  provides a two-way audio path shown at reference  3501 , a loop status output shown at reference  3502 , and a on/off hook control input shown at reference  3503 . These lines are shown connected to call processor  3504  which performs the functions of voice storage and playback, DTMF generation and detection, and call control. Devices which perform the functions of call processor  3504  age well known in the art and many products, such as the Model D41B manufactured by Dialogic Corporation, exist commercially which can accomplish these functions. Also shown is a multi frequency detector module  3505  which is shown connected to the call processor  3504 . A commercially available multi-frequency module capable of performing this function is the Model MF/40 manufactured by Dialogic Corporation. A data network interface  3507  is used to connect the SAF  110  to the other subsystems of the Telephone Control System  1 . Data network interface  3507  passes data messages between the SAF  110  and these other subsystems. The functions of data network interface  3507  are well known in the art, and many products, such as the Model COM4i from Digiboard Corporation, exist commercially which can accomplish these functions. CPU  3506 , which contains a microprocessor, a boot ROM, a RAM, and a disk, controls all functions of the SAF  110 . The trunk interface  3500 , the CPU  3506 , the call processor  3504 , and the data network interface  3507  are all shown connected to an internal data bus  3508 . The CPU  3506  initializes itself at power-up using the boot ROM and then loads a control program into memory which it then executes. The control program allows for the control of simultaneous activities on the trunks  8 . An explanation of the control program for the SAF  110  accompanies FIG.  37 . 
     A flowchart of the operation of E&amp;M control circuit for the trunk interface  3500  of the SAF  115  is shown in FIG.  36 . As the construction of the trunk interface  3500  of FIG. 35 is identical to that of the trunk interface  400  of FIG. 5, the explanation which follows will refer to the reference numbers of FIG. 5 when discussing the internal components of the trunk interface  3500 . Referring now to FIG. 36, the E&amp;M Lead Control Circuit Operation for the SAF Trunk Interface function is entered at step  3600  and control passes to step  3601  where the control circuit  450  idles waiting for an indication from current detector  440  that the E-Lead has gone off-hook. When the E-Lead does go off-hook, control passes to step  3602  where an “Incoming Call” signal is sent to CPU  3506  via buffer  460 . Control then passes to step  3603  where a determination is made as to whether an off-hook signal is received from call processor  3504  signifying that the CPU  3506  is ready to accept the call. If the off hook signal is detected, then control passes to step  3604  where the ‘loop status’  3502  is set active. Control then passes to step  3605  where the M-Lead is winked by taking the M-Lead relay  455  momentarily off-hook. Control then passes to step  3606  where a determination is made as to whether a ‘DID received’ signal  480  is detected. If the signal is not detected then control remains at step  3606 . If the signal is received, indicating that the multifrequency detector  3505  has detected the ‘ANI’ and ‘called number’ digits from the FGD trunk  8 , then control passes to step  3607  where the M-lead relay is once more winked momentarily off hook to acknowledge receipt of the multifrequency data. A 300 millisecond pause is then initiated at step  3608 , prior to taking the M-Lead off hook at  3609  to ‘answer’ the trunk. At this point audio is established by the switch which is providing the FGD service, and the calling party is connected to the SAF  110 . Control then passes to a loop consisting of steps  3610  and  3611 . This loop persists until either at step  3610  the on/off hook signal  3503  is taken on hook by the call processor  3504 , or at  3611  the E-Lead is determined to be on-hook. In either case the call is ended, and control passes to step  3612  where the ‘loop status’ signal  3502  is set inactive. Then at step  3613  a determination is made as to whether the ‘DID received’ signal  480  still remains active indicating. the CPU  3506  is not yet ready to receive a new call. If this signal is still active, then control remains at step  3613 . If it is determined at step  3613  that the ‘DID received’ signal  480  is now inactive, then control passes to step  3614  where the M-Lead is placed on hook, terminating the call, and control passes to step  3601 . 
     A flowchart of the Subscriber Access Facility Main Task is illustrated in FIGS. 37 a  and  37   b - 1 . This program is loaded into memory and executed by SAF CPU  3506 . The Subscriber Access Facility Main Task is entered at step  3700  and control passes to step  3701  where a ‘clear DID received’ signal is sent to the trunk interface  3500 . Control then passes to step  3702  where the ‘incoming call’ signal of the trunk interface  3500  is checked. If this signal is not active then control remains at step  3702 . If this signal is active, then control passes to step  3703 , where the output of the multifrequency detector  3505  is checked via call processor  3504 . The incoming multifrequency digit sequence ‘KP’+‘00’+ANI+‘ST’ is decoded where ‘KP’ is the start digit, ‘ST’ is the stop digit, and the ANI is the phone number of the phone from which the subscriber is calling. Control then passes to step  3704  where, in a similar manner, the incoming multifrequency digit sequence ‘KP’+800+NXX+XXXX+‘ST’ is decoded. Again the ‘KP’ is the start digit, the ‘ST’ is the stop digit, and the sequence 800 NXX XXXX is the phone number dialed by the subscriber to reach the trunk  8 , the NXX being the prefix which identifies trunk group  8  to the PSTN  2 . This phone number represents the programming function which the subscriber wishes to accomplish. Control then passes to step  3705  where a ‘set DID received’ signal is sent to the trunk interface  3500 , indicating that the multifrequency data has been received. Control then passes to step  3706  where a determination is made as to whether the dialed number was of the form 800-NXX-00ab, and if the dialed number was not of this form then control passes to a connector labelled “SAF EXT” at reference  3707 . If at step  3706  it is determined that the dialed number is of the form 800-NXX-00ab, then control passes to step  3710  where a ‘request master record’ message is constructed using the ANI received in step  3703 , and the message is sent via data network interface  3507  to the CPF  100 . Control then passes to step  3711  where a determination is made as to whether a response has been received to the ‘request master record’ message, and if such a response is not received control remains at step  3711 . If the response message is received by network interface  3507 , then control passes to step  3712  where a determination is made as to whether a valid subscriber master record  700  is included in the returned message. If a valid subscriber master record is not included, then control passes to the connector labelled “SAF REORDER” shown at reference  3713 . If at step  3712  a valid subscriber master record  700  is found, then control passes to step  3714  where the DID number  701  is removed from the subscriber master record  700 . Control then passes to step  3715  where a ‘mode memory inquiry’ message is constructed using the DID number  701  and the digits ‘ab’ as detected in step  3706 , and the message is sent via data network interface  3507  to the CPF  100 . Control then passes to step  3716  where a determination is made as to whether a response has been received to the ‘mode memory inquiry’ message, and if such a response is not received control remains at step  3716 . If the response message is received by network interface  3507 , then control passes to step  3717  where a determination is made as to whether a valid mode memory  800  is included in the returned message. If a valid mode memory  800  is not included, then control passes to the connector labelled “SAF REORDER” shown at reference  3718 . If at step  3717  a valid mode memory  800  is found, then control passes to step  3720 , which is identified by a connector labelled “SAF UPDATE” at reference  3719 . At step  3720  a ‘change to new mode memory’ message is constructed, again using DID number  701  and the digits ‘ab’ as detected in step  3706 , and the message is sent via data network interface  3507  to the CPF  100 . Control then passes to step  3721  where the subscriber is prompted by call processor  3504 : “Accepted, you have selected mode memory . . . ‘ab”’, where ‘ab’ are the digits detected in step  3706 . Control then passes to step  3722  where the call processor  3504  causes trunk  8  to be placed on hook, and then control returns to step  3701 . If at step  3706  it is determined that the dialed number was not of the form ‘800-NXX-00ab’, then control passes to a connector labelled “SAF EXT” as shown at reference  3707 . A connector labelled “SAF EXT” is shown at reference  3724 , which causes control to be passed to step  3725  where a determination is made as to whether the dialed number was of the form 800-NXX-cdef, where the digits ‘cd’ do not equal ‘00’. If the dialed number is not of this form, then control passes to a connector labelled “SAF REORDER” shown at reference  3745 . If at step  3725  it is determined that the dialed number is of this form, then control passes to step  3726  where call processor  3504  prompts the subscriber by playing a ‘bong tone’. Control then passes to step  3727  where a determination is made as to whether the subscriber has entered a PIN code, and if the PIN code is not entered control remains at step  3727 . If a PIN code is entered, then control passes to step  3728  where a ‘request master record’ message is constructed using then PIN code entered in step  3727  and the digits ‘cdef’ detected in step  3706 . This message is then sent via data network interface  3507  to the CPF  100 . Control then passes to step  3729  where a determination is made as to whether a response has been received to the ‘request master record’ message, and if such a response is not received control remains at step  3129 . If the response message is received by network interface  3507 , then control passes to step  3750  where a determination is made as to whether a valid subscriber master record  700  is included in the returned message. If a valid subscriber master record is not included, then control passes to the connector labelled “SAF REORDER” shown at reference  3751 . If at step  3750  a valid subscriber master record  700  is found, then this indicates that CPF  100  found a subscriber master record  700  which had a DID number  701  which had the same last four digits as the digits ‘cdef’ detected in step  3706 , and also had the same PIN code  702  as that detected in step  3727 . Control passes to step  3730  where the subscriber is prompted: “Please enter your new mode memory number.” Control then passes to step  3731  where a determination is made as to whether the subscriber has entered a memory number ‘10 to ‘99’, and if such a number has not been entered, then control remains at step  3731 . If a mode memory number is entered, then control passes to step  3732  where a ‘mode memory inquiry’ message is constructed using the DID number  701  and the and the memory number as detected in step  3731 , and the message is sent via data network interface  3507  to the CPF  100 . Control then passes to step  3733  where a determination is made as to whether a response has been received to the ‘mode memory inquiry’ message, and if such a response is not received control remains at step  3733 . If the response message is received by network interface  3507 , then control passes to step  3734  where a determination is made as to whether a valid mode memory  800  is included in the returned message. If a valid mode memory  800  is not included, then control passes to the connector labelled “SAF REORDER” shown at reference  3745 . If at step  3734  a valid mode memory  800  is found, then control passes to step  3735 , where a determination is made as to whether the mode memory which was received in the message requires an ‘externally entered’ memory. This is determined by inspecting the transfer number field of the mode memory  800 . If it has an ‘externally entered number’ tag, then the mode memory does require an ‘externally entered number’. If at step  3735  it is determined that an ‘externally entered number’ is not required, then control passes to a connector labelled “SAF UPDATE” at reference  3736 , which as described earlier causes the mode memory requested to be invoked. If at step  3735  it is determined that an ‘externally entered number’ is required, then control passes to step  3737  where the subscriber master record  700  as acquired at step  3750  is retrieved from memory. Control then passes to step  3738  where the mode memory  800  that was acquired in step  3734  is copied field-by-field to the subscriber master record. Control then passes to step  3740 , where the ANI number acquired in step  3703  is copied to the transfer number field  707  of the subscriber master record  700 . Control then passes to step  3741  where an ‘update master record’ message is constructed using this master record, and the message is sent via data network interface  3507  to CPF  100 . Control then passes to step  3742  where the subscriber is prompted: “Accepted, you have selected mode memory . . . xx”, where the digits ‘xx’ are the digits entered by the subscriber at step  3731 . Control then passes to step  3743  where the trunk  8  is placed on hook, and then control returns to the Subscriber Access Facility Main Task entry point as shown at reference  3748 . If at step  3734 , it is determined that the mode memory received in the message was not valid, then control passes to a connector labelled “SAF REORDER” at reference  3745 , which causes control to pass to step  3746  where the call processor  3504  plays a ‘reorder signal’ to the subscriber, indicating that the call is being terminated. Control then passes to step  3747  where the trunk  8  is paced on hook. Control then returns to the Subscriber Access Facility Main Task entry point as shown at reference  3748 . 
     A block diagram of the Communicator Access Facility (CAF)  125  is illustrated in FIG.  38 . As shown, the CAF  125  contains a serial port interface module  3800  which connects to the serial datalink  10 , and a data network interface  3801  which connects to the high speed data network  150 . The functions of data network interface  3801  are well known in the art, and many products, such as the Model COM4i from Digiboard Corporation, exist commercially which can accomplish these functions. The operation of the CAF  125  is controlled by CPU module  3802 , which consists of a microprocessor, a boot ROM, RAM, and disk. The boot ROM is used to initialize the CPU and load the control program into memory from disk. Operation of the CAF  125  is then controlled by the control program. The control program is described in the explanation which accompanies FIG.  39 . Still referring to FIG. 38, the serial port  3800 , data network interface  3801 , and the CPU module  3802  are all shown connected to internal bus  3803 . 
     A flowchart of the Communicator Access Facility Main Task is illustrated in FIG.  39 . This program is loaded into memory and executed by CPU  3802  of the CAF  125 . The Communicator Access Facility Main Task is entered at step  3900  and control passes to step  3901  where a determination is made as to whether a ‘page message’ is received via data network interface  3801 , and if a ‘page message’ is received then control passes to step  3902  where the page message is sent via serial port  3800  and datalink  10  to packet radio transceiver  9 . Control then passes to step  3903  where an ‘acknowledge timer’ is started, and the ‘page message’ just sent is saved and associated with this ‘acknowledge timer’. Control then passes to step  3904 . Control also passes to step  3904  if a ‘page message’ is not received as determined at step  3901 . At step  3904 , a determination is made as to whether a ‘phone number’ message has been received from a communicator  11  via the serial port interface  3800 . If such a message has been received, then control passes to step  3905  where the subscriber&#39;s DID number  701  is retrieved form the message, and a ‘request master record’ message is created and sent to the CPF  100  via data network interface  3801 . When the response is received from the CPF  100  via the data network interface  3801 , the subscriber master record is retrieved from the response message. Control then passes to step  3906  where the transfer number field  707  of the subscriber master record  700  is updated per the phone number received from the communicator  11  at step  3904 . Control then passes to step  3907  where an ‘update master record’ message is then constructed and sent back to the CPF  100  via data network interface  3801 . Control then passes to step  3908 , where an ‘acknowledge message’ is sent back to the communicator  11  via serial port  3800 . Control then passes to step  3909 . Control also passes to step  3909  if a ‘phone number’ message is not detected at step  3904 . At step  3909  a determination is made as to whether a ‘new mode memory’ message is received from a communicator  11  via serial port  3800 . If this message type has been received then control passes to step  3910  where a ‘change to new mode memory’ message is constructed and sent to CPF  100  via data network interface  3801 , and then control passes to step  3908  where an ‘acknowledge’ message is sent back to the communicator  11  as described earlier. If at step  3909  a ‘new mode memory request’ message is not detected, then control passes to step  3911  where a determination is made as to whether a ‘set dynamic mode assignment mode’ message is received from a communicator  11  via serial port  3800 . If this message type is received, then control passes to step  3912 , where a ‘set dynamic mode assignment flag’ message is constructed and sent to CPF  100  via data network interface  3801 . Control then passes to step  3908  where an ‘acknowledge’ message is sent back to the communicator  11  as described earlier. If at step  3911  a ‘set dynamic mode assignment mode’ message is not detected, then control passes to step  3913  where a determination is made as to whether a ‘disable dynamic mode assignment mode’ message is received from a communicator  11  via serial port  3800 . If this message type is received, then control passes to step  3914 , where a ‘clear dynamic mode assignment flag’ message is constructed and sent to CPF  100  via data network interface  3801 . Control then passes to step  3908  where an ‘acknowledge’ message is sent back to the communicator  11  as described earlier. If at step  3913  a ‘disable dynamic mode assignment mode’ message is not detected, then control passes to step  3915  where a determination is made as to whether the ‘acknowledge timer’ has just expired. If the ‘acknowledge timer’ has just expired, as determined at step  3915 , then control passes to step  3916  where the message which was associated with this ‘acknowledge timer’ is again sent to the communicator  11  via serial port interface  3800 , and control then passes to step  3903 . If at step  3915  it is determined that an ‘acknowledge timer’ has not just expired, then control passes to step  3917  where a determination is made as to whether an ‘acknowledge’ message is received from a communicator via serial port interface  3800 , and if an ‘acknowledge’ message is not received, then control returns to step  3901 . If an ‘acknowledge’ message is received, as determined at step  3917 , then the ‘acknowledge’ timer which is associated with the last message sent to the communicator  11  identified in the ‘acknowledge’ message is cleared. Control then returns to step  3901 . 
     A flowchart of the Communicator Main Task is illustrated in FIG.  40 . This task is executed by microprocessor  200 , and controls all operations of the communicator  11 . The Communicator Main Task is entered at step  4000  and control passes to step  4001  where a determination is made as to whether a ‘page’ message is detected at the receive data input  245 . If a ‘page’ message is detected, and the message contains the pager number which corresponds to this communicator, then control passes to step  4002 , where a signal is sent via output port  250  causing the beeper  260  to generate an alerting sound. Control then passes to step  4003  where a display number is retrieved from the decoded ‘page’ message, and is output to the display  210 . Control then passes to step  4004  where a brief ‘acknowledge’ message is sent via transmit data port  215  to packet data encoder  220  and then to rf transmitter  225 . All RF transmissions from communicator  11  are sent as brief packet. ‘bursts’, thus maintaining a longer life for battery  290 . Control then returns to step  4001 . If at step  4001  it is determined that a ‘page’ message is not received, then control passes to step  4005  where a determination is made as to whether a ‘manual phone number flag’ is set, and if the flag is not set control passes to step  4006  where a determination is made as to whether a data message is received from the ultrasonic transmitter  12  via the serial data input  280 , and if such a message is received then control passes to step  4007 . At step  4007  a determination is made as to whether a ‘auto phone number flag’ is set and if the flag is not set control passes to step  4009  where the ‘auto phone number flag’ is set. Control then passes to step  4010  where the phone number which was embedded in the message received at step  4006  is stored in the memory of microprocessor  200 . Control then passes to step  4011  where a ‘phone number’ message is constructed using the phone number of step  4006 , and the subscriber DID number  701 , as prestored in the RAM of microprocessor  200 . This message is then sent to transmit data port  215 . Control then passes to step  4012  where an ‘acknowledge timer’ is started. Control then passes to step  4013  where a ‘20 second ultrasonic data timer’ is started. Control then returns to step  4001 . If at step  4007  it is determined that the ‘auto phone number flag’ is set, then control passes to step  4008 , where a determination is made as to whether the phone number received embedded in the message at step  4006  is the same as the phone number currently in memory as stored at step  4010 . If the phone numbers match then control passes to step  4013 . If at step  4008  it is determined that the phone numbers are different, indicating that the subscriber has moved to a different room, then control passes to step  4009 . If at step  4005  it is determined that the ‘manual phone number flag’ is set, or if at step  4006  it is determined that a data message is not being received via input port  280 , then control passes to step  4014  where a determination is made as to whether the ‘20 second ultrasonic data timer’ has just expired, and if it has, indicating that the subscriber is no longer near an ultrasonic transmitter  12 , then control passes to step  4015 . At step  4015  the ‘auto phone number flag’ is cleared and control passes to step  4016  there the a ‘new mode memory request’ message is constructed using the stored subscriber DID number  701 , and the stored ‘default mode memory’. Control then passes to step  4017  where an ‘acknowledge timer’ is started, and then control returns to step  4001 . If at step  4014  it is determined that the ‘20 second ultrasonic data timer’ has not just expired, then control passes to step  4018  where a determination is made as to whether the ‘acknowledge timer’ has just expired, and if it has just expired control passes to step  4019  where the message is re-sent via transmit data port  215 . Then at step  4020 , an ‘acknowledge timer’ is started, and then control returns to step  4001 . If at step  4018  it is determined that the ‘acknowledge timer’ has not expired, then control passes to step  4021  where a determination is made as to whether an ‘acknowledge’ message with a pager number that corresponds to this communicator  11  is received via the received data input  245 , and if such a message is received then control passes to step  4022  where the ‘acknowledge timer’ is cleared. Control the returns t step  4001 . If at step  4021  it is determined that an ‘acknowledge’ message is not received, then control passes to step  4023  where a determination is made as to whether the subscriber is entering data via the keypad  205 , and if the subscriber is not entering data, then control returns to step  4001 . If the subscriber is entering data via the keypad, as determined at step  4023 , then control passes to step  4024  where a determination is made as to whether the subscriber wishes to program the Telephone Control System  1  to operate under control of a new mode memory. If this is the case, then control passes to step  4025  where a ‘new mode memory request message’ is constructed and sent to transmit data port  215 , and then control passes to step  4033  where an ‘acknowledge timer’ is started, and then control returns to step  4001 . If at step  4024  it is determined that the subscriber is not selecting a new mode memory, then control passes to step  4026  where a determination is made as to whether the subscriber is selecting the dynamic mode assignment feature, and if this is the case, then control passes to step  4027  where a ‘set dynamic mode assignment mode’ message is constructed and sent to transmit data port  215 , and then control passes to step  4033 . If at step  4026  it is determined that the subscriber is not selecting the dynamic mode assignment feature, then control passes to step  4028  where a determination is made as to whether the subscriber is disabling the dynamic mode assignment feature, and if this is the case, then control passes to step  4029  where a ‘disable dynamic mode assignment mode’ message is constructed and sent to transmit data port  215 , and then control passes to step  4033 . If at step  4028  it is determined that the subscriber is not disabling the dynamic mode assignment mode, then control passes to step  4030  where a determination is made as to whether the subscriber is entering a phone number, and if a phone number is being entered then control passes to step  4031  where the ‘manual phone number flag’ is set. Control then passes to step  4032  where a ‘phone number’ message is constructed using the phone number entered by the subscriber at step  4030 , and this message is transmitted via transmit data port  215 . Control then passes to step  4033 . If at step  4030  it is determined that the subscriber is not entering a phone number, then control passes to step  4034  where a determination is made as to whether the subscriber is selecting the auto-phone number mode, and if this is the case, then control passes to step  4035  where the ‘manual phone number flag’ is cleared, and control then passes to step  4015 . If at step  4034  it is determined that the subscriber is not selecting the auto-phone number mode, then control passes to step  4036 , where a determination is made as to whether the subscriber is entering new program data such a the stored DID number, the stored pager number, and the stored default mode memory. If the subscriber is attempting to modify any of these parameters, then control passes to step  4037  where the new data is stored in the RAM of microprocessor  200 . Otherwise, control returns to step  4001 . As can be understood from the explanation above, one of the primary functions of the Communicator  11  and the Communicator Access Facility  125  is to take the phone number identifying the location of the subscriber, as transmitted by ultrasonic transmitter  12 , and cause that number to be used by the Telephone Control System  1  as the forwarding number for the subscriber. It should also be understood that in a similar fashion the ultrasonic transmitter  12  may transmit a ‘mode memory number’ which, if sent to the Telephone Control System  1  via the Communicator  11  and the Communicator Access Facility  125 , would allow that mode memory to be used by the Telephone Control System  1  to specify the call handling mode for the subscriber. In this case, the Communicator  11  receives a data message from an ultrasonic transmitter  12  and determines that-the message contains a mode memory. The Communicator  11  then transmits a ‘new mode memory request’ message, which includes the subscriber&#39;s DID number  701 , via its RF transmitter  225 . This message is received by packet radio transceiver  9  and sent to the CAF  125  via data line  10 . The CAF  125  then sends a “change to new mode memory” message to CPF  100  via data network interface  3801 . CPF  100  then copies the mode memory referred to in the message to this subscriber&#39;s “subscriber master record”  700 . To further illustrate this process, consider the example of a hospital operating room where an ultrasonic transmitter  12  is transmitting a message containing a mode memory number which corresponds to the “message center” call handling mode. If a doctor, carrying a Communicator  11  enters the operating room, then the Telephone Control System is automatically programmed to send his calls to the “message center.” 
     A block diagram of the Pager Dialing Facility (PDF)  105  is illustrated in FIG.  41 . Standard tip-ring line  5  is shown connected to call processor  4100 , which contains a tip-ring interface, DTMF generators, call progress detectors. The functions of call processor  4100  are well known in the art, and many products, such as the Model D41B manufactured by Dialogic Corporation, exist commercially which can accomplish these functions. The PDF  105  also contains a CPU  4101  which contains a microprocessor, a boot ROM, a RAM, and a disk. The PDF  105  also contains a data network interface module  4103  which connects to the high speed data network  150 . The functions of data network interface  4103  are well known in the art, and many products, such as the Model COM4i from Digiboard Corporation, exist commercially which can accomplish these functions. The call processor  4100 , the CPU  4101 , and the data network interface  4103  are all shown connected to an internal data bus  4102 . The CPU  4101  initializes itself at power-up using the boot ROM and then loads a control program into memory which it then executes. 
     A flowchart of the Pager Dialing Facility Main Task is illustrated in FIG.  42 . This program is loaded into memory and executed by CPU  4101  of the PDF  105 . The Pager Dialing Facility Main Task is entered at step  4200  and control passes to step  4201  where a determination is made as to whether a ‘page’ message is received from CPF  100  via data network interface  4201 , and if the message is not received then control remains at step  4201 . If a ‘page’ message is received, then the ‘pager number’ and the ‘display digits’ are retrieved from the message, and control passes to step  4202  where an ‘attempt count’ is set to a value of 1. Control then passes to step  4203 , where line  5  is taken off hook, and then control passes to step  4204  where call processor  4100  dials the ‘pager number’. Control then passes to step  4205  where a determination is made as to whether the call has not been answered due to a time-out or a non-answer signal such as operator intercept, busy, or reorder. If such a signal or time-out condition is not detected then control passes to step  4206  where a determination is made as to whether the call has been answered by the paging terminal, and if the call has not been answered, control returns to step  4205 . If at step  4206  it is determined that the call is answered, then control passes to step  4207  where a 1 second pause is initiated, and then control passes to step  4208  where the ‘display digits’ are dialed by call processor  4100 . Control then passes to step  4209  where the pager termination digit ‘#’ is dialed, and then control passes to step  4210  where the line  5  is placed on hook. Control then passes to step  4211  where a 2 second delay is initiated before returning control to step  4201 . If at step  4205  it is determined that a time-out or non-answer signal is detected, then control passes to step  4212  where the ‘attempt count’ is incremented. Control then passes to step  4213  where the ‘attempt count’ is checked and if it is found to be not equal to ten then control passes to step  4214  where the line  5  is placed on hook and then after a 2 second pause a step  4215 , control returns to step  4203  to make another attempt at dialing this number. If at step  4213  it is found that the ‘attempt count’ is now equal to 10, then this page is abandoned by returning control to step  4201 . 
     A block diagram of the Client Services Facility (CSF)  130  is illustrated in FIG.  43 . The Client Services Facility (CSF)  130  is used by the service bureau which provides the Telephone Control System service to its subscribers. The CSF  130  allows a client services representative to gain access to the database contained in the CPF  100 , and thus be able to review and modify the subscriber master records  700  and mode memories  800  of the subscribers. The CSF  130  contains a CPU  4300  which contains a microprocessor, a boot ROM, a RAM, and a disk. The CSF  130  also contains a data network interface module  4301  which connects to the high speed data network  150 . The functions of data network interface  4301  are well known in the art, and many products, such as the Model COM4i from Digiboard Corporation, exist commercially which can accomplish these functions. Also shown is a display monitor  4302 , and a keyboard  4303 . The CPU  4300  initializes itself at power-up using the boot ROM and then loads a control program into memory which it then executes. 
     A flowchart of the Client Services Facility Main Program is illustrated in FIG.  44 . This program is loaded into memory and executed by CPU  4300  of the CSF  130 . The Client Services Facility Main Program is entered at step  4400  and control passes to step  4401  where a determination is made as to whether the client services representative has entered the DID number for a particular subscriber and has requested a subscriber master record  700 , and if this is the case then control passes to step  4402  where a ‘request master record’ message is sent via data network interface  4301  to CPF  100 . Control then passes to step  4403  where the subscriber master record  700  is removed from the response message from the CPF  100 , and is displayed on monitor  4302 . Then at step  4404 , the client services representative is allowed to review and modify the contents of the subscriber master record  700  using monitor  4302  and keyboard  4303 . Then at Step  4405  a determination is made as to whether the client services representative is completed with this operation, and if not, then control returns to step  4404 . When the operation is complete, then control passes to step  4406  where an ‘update master record’ message is constructed and sent to CPF  100  via data network interface  4301 . Control then returns to step  4401 . If at step  4401  it is determined that the client services representative is not requesting a subscriber master record  700 , then control passes to step  4407  where a determination is made as to whether the client services representative has entered the DID number for a particular subscriber and has requested a subscriber mode memory  800 , and if this is the case then control passes to step  4408  where a ‘mode memory inquiry’ message is sent via data network interface  4301  to CPF  100 . Control then passes to step  4409  where the mode memory  800  is removed from the response message from the CPF  100 , and is displayed on monitor  4302 . Then at step  4410 , the client services representative is allowed to review and modify the contents of the mode memory  800  using monitor  4302  and keyboard  4303 . Then at step  4411  a determination is made as to whether the client services representative is completed with this operation, and if not, then control returns to step  4410 . When the operation is complete, then control passes to step  4412  where an ‘update mode memory’ message is constructed and sent to CPF  100  via data network interface  4301 . Control then returns to step  4401 . If at step  4407  it is determined that the client services representative is not requesting a new mode memory, the control passes to step  4413  where a determination is made as to whether the client services representative has entered a DID number and wishes to activate a new subscriber for this number. If this is the case then control passes to step  4414  where a ‘create a new subscriber message’ is generated with this DID number and the message is sent to CPF  100  via data network interface  4301 . Control then returns to step  4401 . If at step  4413  it is determines that the client services representative does not wish to create a new subscriber, then control returns to step  4401 . 
     While a preferred embodiment of the invention has been described in detail, it should be apparent that many modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. 
     For example, while the preferred embodiment of the control system provides voice synthesized type courtesy messages, any appropriate tones, beeps, etc. would serve as a courtesy message and such is the use of that term throughout the claims appended hereto. In addition, the term “line” as used herein and in the claims appended hereto includes both lines and trunks. 
     In addition, whereas the preferred embodiment of the invention uses the term “line” to describe the interconnecting medium between the control system and the central exchange, it should be understood throughout the specification and claims that “line” refers to tip and ring pairs, trunks or any other form of connecting circuits.