Abstract:
The system for providing calling party privacy during subscriber call screening for a central office switching system enables a subscriber to monitor and intercept the last forwarded, active call to the Voice Messaging System, while providing the calling party with privacy as the voice messaging system provides the prerecorded instructions/message to the calling party. The calling party privacy feature delays call screening alerting to the subscriber to prevent the subscriber from monitoring the call connection until the calling party is recording their message on the voice messaging system. Depending on the method used, once the calling party privacy feature requirements are satisfied, the subscriber call screening system notifies the subscriber of the presence of a calling party who is recording a message for the subscriber on the Voice Messaging System.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to U.S. patent application Ser. No. 09/134,267, titled “Method and Apparatus for Direct Voice Mail Screening, Monitoring, and Retrieval” filed on Aug. 14, 1998 and U.S. patent application Ser. No. 09/220,256, titled “Subscriber Directed Message Processing System” filed on Aug. 14, 1998. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to telephone switching systems served by a Voice Messaging System which enables a calling party to leave a message for a subscriber and, in particular, to a subscriber call screening system that allows a subscriber to monitor the message being recorded by the calling party and ensures calling party privacy during voice mail announcements. 
     PROBLEM 
     There is a need in the field of telephone switching systems to provide the subscriber with increased functionality beyond the simple recording of messages from a calling party. In particular, the traditional answering machine system served as the mechanism to enable a calling party to alert the subscriber that a call was attempted, in the form of a brief audio message from the calling party regarding the reason for the call and the identity of the calling party. The subscriber can then later activate the answering machine system to retrieve these recorded messages. Customer premises-based answering machines typically also provide a rudimentary call screening capability. In particular, the answering machine outputs the entirety of the message recording transaction via a loudspeaker during the message recording process. This enables the subscriber to listen to the message as it is being recorded, and optionally pick up the telephone to barge in on the call connection and speak to the calling party. 
     In contrast, voice messaging services that are provided by centralized switching apparatus, such as central office switching systems and customer-premises switching systems, do not enable a subscriber to listen to and/or screen an incoming voice message as the calling party is presently recording the message. These central office switching systems redirect the incoming call connection to the voice messaging system as soon as the central office switching system call processing indicates that the voice message function is required. Thus, the traditional central office switching system based voice messaging systems simply enable a calling party to leave a message which the subscriber can later retrieve. The ability to screen calls forwarded to a voice messaging system has been requested by the telephone operating companies to increase the market penetration of revenue enhancing voice mail systems. Such a central office switching system based voice messaging call screening service has been generically proposed in GR-1512-Core, for Call Screening. 
     The problem that needs to be addressed is a privacy issue with regard to the call screening capability for calls forwarded to voice messaging systems. The calling party has an expectation of privacy during the time the voice messaging system provides the prerecorded instructions/message to the calling party and is thus likely to speak freely, not expecting their comments to be overheard or recorded during this process. If the subscriber can monitor the voice messaging connection, during this time interval, the calling party&#39;s comments are conveyed to the subscriber without the calling party being aware of this condition. Thus, in the field of central office switching systems, there is no capability to provide the calling party with privacy, as the voice messaging system provides the prerecorded instructions to the calling party. 
     SOLUTION 
     The above-described problem is solved and a technical advance achieved by the calling party privacy feature of a subscriber call screening system for a central office switching system, which enables a subscriber to monitor and intercept the last forwarded, active call to the Voice Messaging System, while providing the calling party with privacy as the voice messaging system provides the prerecorded instructions/message to the calling party. The calling party privacy feature delays call screening alerting to the subscriber to prevent the subscriber from monitoring the call connection until the calling party is recording their message on the voice messaging system. Depending on the method used, once the calling party privacy feature requirements are satisfied, the subscriber call screening system notifies the subscriber of the presence of a calling party who is recording a message for the subscriber on the Voice Messaging System. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 illustrates in block diagram form, the overall architecture of the environment in which the subscriber call screening system and the calling party privacy feature are operational; and 
     FIGS. 2 and 3 illustrate in flow diagram form the operation of the calling party privacy feature of the subscriber call screening system for a voice messaging system in processing a typical call scenario. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates in block diagram form, the overall architecture of the environment in which the subscriber call screening system and the calling party privacy feature are operational. In particular, the subscriber call screening system and the calling party privacy feature are operational in a communications network environment, such as in the local central office switch of the Public Switched Telephone Network (PSTN) or a customer premises based switching system or even an Internet Provider network (collectively termed “communications system” herein). The communications system offers a voice messaging service as part of its operational capabilities via an adjunct Voice Messaging System that is cooperatively operational with the communications system. The Voice Messaging System comprises a memory in which are stored the voice messages that are received from calling parties. The Voice Messaging System itself includes a message controller that regulates the storage and playback of the voice messages that are stored in memory. 
     Incoming Call Initiation 
     A calling party at telephone station set  111  initiates a call connection to the telephone station set  122  of the subscriber in well known manner through their local central office switch, communications system  101 . In particular, the communications network comprises a traditional voice communications network that includes a plurality of local communications systems  101 - 102 , such as telephone switching systems that are part of the Public Switched Telephone Network (PSTN)  100  and are interconnected via trunk circuits to an Interexchange Carrier System (IXC)  103 . Each of the communications systems  101 ,  102  serve a plurality of telephone station sets and the communications systems  101 ,  102  may be interconnected via an out of band signaling link CS through the Interexchange Carrier System (IXC)  103 , using the well known SS 7  signaling protocol. The operation of such a communications network is well known and is not described in detail herein. The communications systems  101 ,  102  provide a set of features and services to the telephone station sets that they serve. In addition, an adjunct Voice Messaging System  121  is connected to communications system  102  to enable incoming calls to be redirected to the Voice Messaging System  121  to thereby enable a calling party to leave a voice message for subscribers of communications system  102 . In addition, communications system  102  is equipped with the subscriber call screening system CHN 2 , that is operational in the controller  102 C of the communications system  102 . In this description, the subscriber call screening system CHN 2  is shown as resident in the controller  102 C, which transmits control data to the directly connected Voice Messaging System  121 . Note that the call connection can be between telephone station sets (such as  123 ,  122 ) served by the same communications system  102 . The example of the use of two communications systems  101 ,  102  to implement the call connection is selected for the purpose of illustration, not to limit the applicability of the concept taught herein. 
     Voice Mail Message Processing Example 
     In order to illustrate the operation of the present subscriber call screening system for a voice messaging system CHN 2 , an example of a typical call connection is described, in flow diagram form in FIGS. 2 and 3, with respect to the system architecture of FIG.  1 . In particular, a communication connection is established between the calling party, located at telephone station set  111 , and the subscriber, located at telephone station set  122 . This is accomplished for example by the calling party at telephone station set  111  going off-hook at step  201  and dialing the telephone number of the subscriber located at telephone station set  122  at step  202 . In response to the dialed digits, the controller  101 C of communications system  101  at step  203  causes a call connection to be extended over path  1  to the lnterexchange Carrier System  103 , which, in response to control signals received from controller  101 C over control channel CS, extends this call connection over path  2  to communications system  102  at step  204 . The control signals originated by the controller  101 C are propagated by the lnterexchange Carrier System  103  to the controller  102 C of communications system  102 . The controller  102 C responds to the received control signals by further extending the call connection over path  3  to the telephone station set  122  of the subscriber at step  205 . The subscriber is provided with a voice mail feature by use of the Voice Messaging System  121  by the communication system  102 , which voice mail feature is activated in response to the occurrence of one of a plurality of conditions. For example, the subscriber may activate a do not disturb feature, which automatically redirects incoming calls that are directed to the subscriber telephone station set to the Voice Messaging System  121  over path  4 . Alternatively, the subscriber may be active on the telephone station set  122  on an existing call connection, or the incoming call can be redirected to the Voice Messaging System  121  after a predetermined number of ringing cycles at the unanswered telephone station set  122 . The telephone station set  122  can also be equipped with call screening redirection, where incoming calls from selected calling parties are automatically redirected to the Voice Messaging System  121 . 
     In any case, once call processing determines that the incoming call is to be redirected to the Voice Messaging System  121 , the incoming call is completed at step  206 A through the telecommunication system  102  to the Voice Messaging System  121 . Traditionally, this is the conclusion of the call processing as far as the subscriber&#39;s ability to intervene in this incoming call. 
     Call Screening with Calling Party Privacy Feature 
     Once the incoming call has been redirected to the Voice Messaging System at step  206 A, the calling party privacy feature invokes the privacy period for the calling party at step  206 B and thus delays the application of the special alert signal to the subscriber&#39;s telephone station set  122 . This privacy period can be created in a number of ways. Calling party privacy can be provided until the prerecorded message provided by the Voice Messaging System completes, or a programmable timer can be used to ensure that a predetermined period of time has elapsed from the initial connection of the calling party to the voice messaging system, or a timer function can be enabled based upon the timeout of the event that initiated the call forwarding to the voice messaging system. In any of these instances or other like implementations, the subscriber call screening system CHN 2  prevents or delays the subscriber from monitoring the call connection until the calling party begins recording their message on the voice messaging system to ensure privacy of the calling party. Once the calling party privacy feature delay processing has been completed, at step  207 , the subscriber call screening system CHN 2  determines the state of the subscriber&#39;s line. If the subscriber is presently engaged in an existing call connection, processing remains in the subscriber line condition determining state by cycling through the decision steps of step  208  where the present state of the redirected call is determined to ensure that the calling party is still on the message connection to the Voice Messaging System  121  and returns to step  207  where the subscriber call screening system CHN 2  determines the state of the subscriber&#39;s line. If the calling party disconnects from the Voice Messaging System  121  at step  208  prior to the subscriber completing the existing call connection, then call processing exits at step  209 , since the calling party is no longer present on a message connection to the Voice Messaging System  121  such that monitoring or intercept by the subscriber is then possible. Otherwise, if the subscriber is not engaged in an existing call, or has gone on-hook from an existing call connection while the calling party is still engaged in a message connection to the Voice Messaging System  121  at step  210 , processing advances to step  211  where the subscriber call screening system CHN 2  enters the call screening mode and transmits a special subscriber sensible alert signal to the subscriber&#39;s telephone station set  122  in the form of an audible and/or visual indication, such as a ping ring signal. 
     Once the call screening tone is provided, the call screening phase is initiated at step  213 , which is the time during which the subscriber can go off-hook on the subscriber telephone station set  122  to engage the call screening function. If the calling party or the Voice Messaging System  121  terminates the message connection before the subscriber goes off-hook or the call screening time interval expires, the call is no longer available for screening and call processing exits at step  209 . The next stage of the call screening function is the Monitor Stage, which is initiated at step  212  when the subscriber goes off-hook on the subscriber telephone station set  122  during the call screening stage to listen to the forwarded call (message connection) without the calling party&#39;s knowledge. In response to the subscriber going off-hook on the subscriber telephone station set  122 , the subscriber call screening system CHN 2  at step  214  establishes a three-way connection between the subscriber telephone station set  122 , the calling party and their message connection to the Voice Messaging System  121 , to monitor the calling party. 
     In addition, the monitor stage may have its duration limited to conserve the three way conference circuit resources. The Intercept Stage of the subscriber call screening system CHN 2  is enabled by the subscriber at step  215  when the subscriber in the monitor stage initiates a switch hook flash to intercept the message connection and establish two way call communication with the calling party. 
     Call screening is activated and deactivated via dial codes that are entered by the subscriber in well known fashion. The subscriber call screening system CHN 2  provides a confirmation tone when the subscriber activates or deactivates the call screening function. 
     Summary 
     The calling party privacy feature of a subscriber call screening system operates in central office switching systems to provide additional functionality by providing privacy to the calling party during the time interval when the voice messaging system provides the prerecorded instructions to the calling party. This privacy is provided by delaying the special alert signal, provided by the subscriber call screening system to the subscriber for a call eligible for screening, until the calling party is recording a message.