Abstract:
An advanced intelligent network telephone system for terminating calls to subscribers to a privacy screening service, when the calling party has a private telephone number. Privacy screening services allow a subscriber to manage and monitor incoming telephone calls, such that unwanted calls are not terminated to the subscriber. When a calling party dials the telephone number of a subscriber to a privacy screening service, the system manages the call according to whether the calling party number is known and public, known and private, or unknown. If the calling party number is known and public, the call is routed to the subscriber. If the calling party is known and private, the call is routed to a service node, which plays an announcement to the calling party, asking the calling party for permission to override his or her privacy. If the calling party agrees, the service node dials a customized dialing plan (CDP) code that triggers an info_analyzed query from the service node&#39;s service switching point (SSP) to a service control point (SCP). If the calling party is unknown, the service node asks the calling party to record his or her name. If the calling party records his or her name, the service node dials a CDP code, that triggers an info_analyzed query to the SCP.

Description:
BACKGROUND 
     1. Field of the Invention 
     The present invention relates to the termination of telephone calls in a telephone network that provides a privacy screening service to its subscribers. 
     2. Background of the Invention 
     A privacy screening service is a service that allows a subscriber to the privacy screening service to screen incoming calls. The privacy screening service provides information to the called party (in this case, the subscriber to the privacy screening service) that allows the subscriber to make an informed decision as whether or not to answer the call. For example, a subscriber may use the privacy screening service to block all unidentified calls from going through. Private telephone numbers are telephone numbers that block services such as “caller ID” that would otherwise identify the caller to the called party. In telephone systems that offer private numbers and a privacy screening service to its customers, calls from a private number to a subscriber with the privacy screening service cannot be completed automatically, unless the caller authorizes the system to override the privacy of his number. 
     FIG. 1 is a schematic diagram showing the basic architecture of an Advanced Intelligent Network telephone system. The Advanced Intelligent Network System is described in U.S. Pat. No. 5,701,301 and U.S. Pat. No. 5,838,774, which are hereby incorporated by reference. FIG. 1 shows the caller&#39;s telephone  101  which is connected via the calling party&#39;s voice line  102   a  to its Service Switching Point (SSP)  103 . SSP  103  is connected via voice trunk  102   b  to a second SSP (SSP  104 ). SSP  104  is the SSP that services the called party&#39;s telephone  105 . In this example, the called party is a subscriber who has subscribed to the privacy screening service. (The called party will also be referred to as the “subscriber” as well as the “called party” herein.) FIG. 1 also shows a Signaling Transfer Point (STP)  106  which services a Service Control Point (SCP)  107  and a third SSP (SSP  108 ) which services a Service Node (SN)  109 . SCP  107  has a database  107   a  that contains subscriber information. 
     STP  106  is a signaling hub that routes packets of data over the common channel signaling network. Common channeling signaling networks are data communications networks laid over the system&#39;s switching network that carry data and control messages to and from and among the SSPs, STPs, and SCPs in the network. Signaling System  7  (SS7) is the protocol that runs over common channel signaling networks. A common channel signaling network using the Signaling System 7 protocol is often referred to as an SS7 network. The SS7 network carries data and control messages to the SSPs in the telephone network. SCPs are powerful fault-tolerant computers, e.g., AT&amp;T Star Server FT Model 3200 or AT&amp;T Star Server FT Model 3300 computers (these and more current computers such as the Advantage P200 and Advantage 4P200 models are presently available from Lucent Technologies). SCPs are “intelligence centers” with access to applications databases that enable the network to deliver advanced services such as caller ID, privacy screening and call forwarding. The SCPs also execute service package applications (SPAs) that deliver the advanced services. SNs are physically generally similar to SCPs, but include voice and Dual Tone Multi-Frequency (DTMF) signal recognition circuits, voice synthesizers, and voice recognition and digit collection capabilities. The operators of the telephone network can program their SNs to manage data, to respond to calls and to route calls as specified by the telephone network, and to collect digits from a caller or subscriber. The SN&#39;s voice circuits can also be programmed to provide a voice response (e.g., to play pre-selected announcements) to callers and to perform voice recognition. SNs can also be programmed to respond to input from the callers by, e.g., further routing the call. 
     As shown in FIG. 1, STP  106  controls communications between SSPs  103 ,  104  arid  108  and SCP  107 . The SSPs are connected to the caller&#39;s and the subscriber&#39;s telephones and to each other via voice lines  102   a  and  102   c  and via voice trunks  102   b  and  102   d . The SSPs communicate with STP  106  and SCP  107  via SS7 data links  110   a ,  110   b ,  110   c  and  110   d . SN  109  is connected to SSP  108  by an Integrated Service Digital Network (ISDN) Basic Rate Interface (BRI) line  111 . 
     When the caller places a call to the subscriber, the call is routed by SSP  103  to SSP  104 . FIG. 1 a  shows a prior art system in which call  1  is routed from the caller to SSP  103  and then to SSP  104 . Because the subscriber has subscribed to the privacy screening service, that call (like all calls to that subscriber&#39;s number) triggers a “termination attempt trigger” or TAT. In response to the TAT, SSP  104  issues query  2 , shown in FIG. 1 a . Query  2  is a message that goes up to SCP  107  via STP  106  asking for directions as to how the call should be terminated. The query includes the following information: the subscriber&#39;s telephone number (in the called party field), the calling party&#39;s telephone number (in the calling party field), the calling party&#39;s presentation restriction indicator (also in the calling party field), and, optionally, the trigger criteria type (indicating the service for which the query is intended). 
     SCP  107  checks the presentation indicator in the calling party field of the query received as a result of the termination attempt trigger. If presentation of the caller&#39;s number is not restricted, i.e., if the caller&#39;s number is public, SCP  107  sends back a response (response  3  in FIG. 1 a ) instructing SSP  104  to terminate the call, and to supply the caller&#39;s telephone number (and, if the subscriber has subscribed to a higher level of service such as caller ID deluxe, the caller&#39;s name and telephone number). In that case, SSP  104  terminates the call (call  1 ′ in FIG. 1 a ), i.e., completes the call, supplying the subscriber with the caller&#39;s number (and possibly also with the caller&#39;s name). If the caller&#39;s name is to be supplied to the customer, SSP  104  launches another query, a TR 1188  CNAM query to the SCP, to obtain the caller&#39;s name from either database  107   a  or another database on the system that contains the names corresponding to the telephone numbers. 
     The prior art system of FIG. 1 a  asks the calling party to record his or her name whenever the calling party number is private or unknown. In this prior art system, if the caller&#39;s number is private or unknown, SCP  107  enters the subscriber&#39;s number in the calling party field in response  3  and directs SSP  104  to forward the call to SN  109  (call  1 ″ in FIG. 1 a ). When SN  109  answers the call, it asks the calling party to record his or her name. If the calling party responds by recording his or her name, SN  109  then calls the subscriber (call  4  in FIG. 1 a ), using the subscriber&#39;s telephone number (that had been stored in the calling party field). 
     The TAT provisioned on the subscriber&#39;s line at SSP  104  triggers a second time, sending a query (query  5 ) up to SCP  107  through STP  106 . SCP  107  recognizes that this call originated with a service node, SN  109 , and sends a response (response  6  in FIG.  1   a ) authorizing termination to the subscriber. SN  109  then plays a dialog to the subscriber, identifying the calling party by playing the calling party&#39;s recorded name for the subscriber. If the subscriber chooses to accept the call, the call is put through (leg  4 ′ of call  4  in FIG. 1 a ). If the subscriber refuses to accept the call, the calling party is informed that his or her call was not accepted, and the call is disconnected. 
     This prior art system works irrespective of whether the calling party number is public (i.e., not private), private or unknown, but cannot take full advantage of the advanced intelligent network capabilities of the AIN system, because the calling party number is not preserved. Thus this prior art system does not allow the use of advanced intelligent network features such as call return or call trace. 
     SUMMARY OF THE INVENTION 
     The present invention is a system and method that allows calls to be terminated to a subscriber to a privacy screening service, even when the calling party is either private or unknown, and preserves the calling party number when the calling party number is known (whether the calling party number is public or private). The present invention is illustrated in FIGS. 2-3, which show the same basic AIN architecture as the network architecture of prior art systems of FIGS. 1-1 a . FIG. 2 shows the operation of the present invention when the calling party is known (for both the case when the calling party number is private and the case when the calling party number is public). FIG. 3 shows the operation of the invention when the calling party number is unknown. 
     As shown in FIG. 2, when the calling party dials the subscriber&#39;s number, the call is routed (as call  1  in FIG. 2) through the caller&#39;s SSP (SSP  103 ), to the subscriber&#39;s SSP, SSP  104 . The call hits the subscriber&#39;s TAT at SSP  104 , triggering a query (query  2 ) in FIG. 2, which goes up to SCP  107  via STP  106 , over SS7 links  110   b  and  110   d  (links  110   b  and  110   d  are identified in FIG. 1, but are not identified in FIGS.  2 - 3 ). 
     SCP  107  checks the calling party ID and presentation indicator in query  2 , and determines whether the calling party is known and public, known and private, or unknown. In the present invention, if the calling party number is public and known, SCP  107  sends back a response authorizing termination to the subscriber (response  3  in FIG.  2 ). If the subscriber has subscribed to a service that provides the calling party&#39;s name as well as the calling party&#39;s telephone number, SSP  104  then launches a query (e.g., a TR- 1188  query) to obtain calling name information from SCP  107  and its database  107   a . Then SSP  104  terminates the call to the subscriber (call  1 ′ in FIG.  2 ), presenting the subscriber with the calling party&#39;s number (and name, if the subscriber has subscribed to a service that provides the calling party&#39;s name as well as the calling party&#39;s number). 
     If the calling party number is private, SCP  107  re-writes the presentation indicator as “public”, i.e., redefines the presentation indicator in the presentation indicator field (i.e., the presentation_restricted_indicator portion of the calling party ID field in the query) as public. As shown in FIG. 2, SCP  107  responds to the TAT query from SSP  104  by directing SSP  104  to forward the call to SN  109 , with the presentation indicator re-written as public. SSP  104  writes the subscriber&#39;s number in the “re-directing party” field, and forwards the call (call  1 ″ from SSP  104  to SN  109  in FIG. 2) to SN  109  at SN  109 &#39;s number via SSP  108 . Thus, when the call is presented to SN  109 , the call has the subscriber&#39;s number in the “re-directing party” field, and the original calling party&#39;s number in the “calling party” field. Because SCP  107  has toggled the presentation indicator from “private” to “public”, SN  109  has access to the calling party number. SN  109  answers the call, and plays an announcement to the calling party, asking for his/her permission to present his/her number (and name) to the subscriber. If the calling party refuses to grant permission to present his/her number (and name) to the subscriber, the call is disconnected. If the calling party agrees to have his/her number (and name) presented, SN  109  dials a Customized Dialing Plan (CDP) code Y (e.g., * 95 ), the 10-digit called party number, and the 10-digit calling party number (call  4  in FIG.  2 ). 
     The CDP code Y triggers a query at SSP  108 , which launches an info_analyzed query to SCP  107  (query  4 ′ in FIG.  2 ), populating the “Access Code” and “Collected Digits” fields as follows: 
     Access Code=Y 
     Collected Digits=The remainder of the dialed digits, i.e., the 10-digit called party number followed by the 10-digit calling party number. 
     SCP  107  analyzes the dialed string and returns an analyze_route response (response  5 ) with: 
     CdPN=Subscriber&#39;s number 
     CgPN=Calling party number 
     SSP  108  then dials the subscriber number (call  6  in FIG.  2 ). This call is routed through SSP  104 , where it triggers a TAT query (query  7 ) from SSP  104  to SCP  107  with the following parameters: 
     CgPN=Calling party number 
     CdPN=Subscriber&#39;s number 
     Charge Number=SN  109 &#39;s number, e.g., lead number for SN  109 &#39;s Multi Line Hunt Group (MLHG) number 
     SCP  107  recognizes the Charge Number as SN  109 &#39;s MLHG number, and authorizes SSP  104  to terminate the call (response  8 ). SSP  104  then presents the call to the subscriber (call  1 ′ in FIG. 2, with the presentation indicator set to “public”). SSP  104  obtains the calling party&#39;s name by sending a CNAM TR- 1188  query to SCP  107  (or to another SCP that responds to TR- 1188  CNAM queries). As soon as the subscriber&#39;s telephone rings, SN  109  can drop out of the route, with the call routed through SSPs  103 ,  104 ,  108  and  104  (again) and on to the subscriber. 
     FIG. 3 shows the operation of the present invention when the calling party is unknown. As above, the sequence starts when the calling party dials the subscriber&#39;s number. The call is routed (as call  1  in FIG. 3) through the caller&#39;s SSP, SSP  103 , to the subscriber&#39;s SSP, SSP  104 . The call hits the subscriber&#39;s TAT at SSP  104 , triggering a query (query  2  in FIG.  3 ), which goes up to SCP  107  via STP  106 , over SS7 links  110   b  and  110   d . SCP  107  examines the presentation indicator in the calling party ID field in query  2 , and determines that the calling party number is unknown. 
     In response  3  to query  2 , SCP  107  then directs SSP  104  to route the call to SN  109  (call  1 ′ from SSP  104  to SN  109  in FIG.  3 ). The call arrives at SN  109  with the subscriber as the redirecting party, the calling party number in the calling party field, and the SN number in the called party field. When the call is presented to SN  109 , SN  109  checks the calling party number, and determines that it is unknown. SN  109  then plays an announcement to the calling party, asking the calling party to record his or her name. If the calling party refuses to do so, the call is disconnected. If the calling party agrees to record his/her name, SN  109  dials the CDP code Y, the 10-digit called party number, and the 10-digit SN Multi Line Hunt Group number (call  4  in FIG.  3 ). The CDP code Y triggers a query at SSP  108 , which sends an info_analyzed query (query  4 ′ in FIG. 3) to SCP  107 , populating the “Access Code” and “Collected Digits” fields as follows: 
     Access Code=Y 
     Collected Digits=the remainder of the dialed digits, i.e., the 10 digit called party number and the 10-digit SN MLHG number. 
     SCP  107  analyzes the query and returns an analyze_route message (response  5 ) to SSP  108 , which then calls the subscriber (call  6 ) with: 
     CdPN=subscriber&#39;s number 
     CgPN=SN&#39;s MLHG number. 
     This call triggers a TAT query (query  7 ) on the subscriber&#39;s line at SSP  104 . The query includes SN  109 &#39;s MLHG number as the calling party number, the subscriber&#39;s number as the called party number, and SN  109 &#39;s MLHG number as the charge number. Since the charge number is the lead number for SN  109 &#39;s MLHG, SCP  107  sends SSP  104  an Authorize Termination message (response  8 ), authorizing termination of the call from SSP  104  to the subscriber. SSP  104  then executes a TR 1188  query, which returns the privacy manager as the calling party name. SSP  104  then completes the call (call  1 ″). For subscribers to caller ID deluxe, the LCD display on the subscriber&#39;s telephone will show, e.g., “Privacy Manager” as the calling party. 
     SN  109  then plays an announcement to the subscriber, asking the subscriber whether he or she would like to accept or reject a call from the calling party, whose name is played for the subscriber as “recorded name.” The subscriber can then, e.g., accept the call by pressing 1, have a simple rejection played by pressing 2, have a “sales call” rejection (“we do not accept sales calls, please remove this number from your caller list”) played by pressing 3, or route the call to voicemail by pressing 4. If the subscriber accepts the call, SN  109  transfers control of the call to SSP  104 , and drops out (although the call is still routed through SSP  108 ). If the subscriber rejects the call, SN  109  plays the announcement selected by the subscriber or routes the call to voicemail, and then the call is disconnected. 
     The present invention thus preserves the calling party number, such that the system can take full advantage of the capabilities of the advanced intelligent network, e.g., call return or call trace for all known calls, whether private or public. 
     It is an object of the present invention to offer a privacy screening service to subscribers that allows private calling parties to override their privacy, and that allows calls from unknown calling parties to be routed to the subscriber, and yet still allows the use of advanced intelligent network features. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic diagram showing the basic architecture of an AIN telephone network. 
     FIG. 1 a  is a schematic diagram showing a prior art system&#39;s routing of calls when a subscriber has subscribed to a privacy screening service. 
     FIG. 2 is a schematic diagram of the present invention, showing the routing of calls when a subscriber has subscribed to a privacy screening service and the calling party number is known. 
     FIG. 3 is a schematic diagram of the present invention, showing the routing of calls when a subscriber has subscribed to a privacy screening service and the calling party number is unknown. 
     FIG. 4 is an overall schematic diagram of the call flows of the present invention, showing how the call flows depend upon whether the calling party number is public, private or unknown. 
     FIG. 5 is a chart outlining the call flows of the present invention, when the subscriber has subscribed to a privacy screening service, and the calling party&#39;s number is known and public. 
     FIGS. 6-6 a  are charts outlining the call flows of the present invention, when the subscriber has subscribed to a privacy screening service that provides the name and the number of the calling party, and the calling party&#39;s number is known and private. 
     FIGS. 7-7 a  are charts outlining the call flows of the present invention, when the subscriber has subscribed to a privacy screening service, and the calling party&#39;s number is unknown. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention can be described by describing the sequence of call flows initiated when a calling party calls a subscriber who has subscribed to a privacy screening service. FIG. 4 is an overall schematic showing that the call flows depend on whether the calling party number is known and public (further described in Example 1 and FIG.  5 ), known and private (further described in Example 2 and FIGS. 6-6 a ) or unknown (further described in Example 3 and FIGS. 7-7 a ). As shown in FIG. 4, the call sequence starts in step  401 , when the calling party dials the subscriber&#39;s telephone number. The calling party&#39;s SSP, SSP  103 , routes the call to the subscriber&#39;s SSP, SSP  104  in step  402 . Because the subscriber has subscribed to a privacy screening service, in step  403  that call hits a termination attempt trigger or TAT at SSP  104 . In response to the TAT, SSP  104  sends a query up to SCP  107  in step  404 . In step  405 , SCP  107  determines whether (1) the calling party number is known and public, in which case the call is routed to the subscriber in step  406 , as described in Example 1 and FIG. 5; (2) the calling party number is known and private, in which case the call is routed to SN  109 , which asks the calling party to override his or her privacy (step  407 ), the calling party agrees or refuses (step  408 ) and then SN  109  routes the call to the subscriber if the calling party agrees (step  409 A) or disconnects the call if the calling party refuses (step  409 R), as described in Example 2 and FIGS. 6-6 a ; or (3) the calling party number is unknown, in which case the call is also routed to SN  109 , SN  109  asks the calling party to record his or her name in step  410 , the calling party refuses or agrees to record his or her name in step  411 , and then the call is disconnected (step  412 R) or routed to the subscriber (step  412 A). This sequence for unknown calling parties is described in Example 3 and FIGS. 7-7 a.    
     As discussed above, FIGS. 5-7 a  represent schematically the call flows corresponding to the cases described below in Examples 1-3. The acronyms used in FIGS. 5-7 a  are: 
     Calling Party Number: CgPN 
     Called Party Number: CdPN 
     Charge Number: ChargeN 
     Re-Directing Party ID: Re-DirectID 
     Presentation indicator: Privacy 
     Display Text: DspTxt 
     Announcement Identification: AnnID 
     Collect Digits: CollDig 
     The announcements played by the network will be exemplified as follows: 
       91 : Announcement to an unknown calling party, asking the calling party to record his/her name. 
       92 : Announcement to the subscriber, playing the calling party&#39;s name, and asking the subscriber to accept or reject the call. 
       93 : Announcement to the calling party when the calling party&#39;s number is private, asking the calling party for permission to provide his/her number (and name) to the subscriber, and explaining that if permission is not granted, the call will be disconnected. 
     For the purpose of illustrating the invention with specific examples, the flow charts in FIGS. 5-7 a  will all have the calling party number (CgPN) as 111-111-1111, the subscriber&#39;s number (initially, CdPN) as 222-222-2222, and the Service Node&#39;s Multi-Line Hunt Group number as 333-333-3333. 
     The specific sequence of calls depends on the private/public/unknown status of the calling party. As described in Examples 1-3, there are three possible call sequences. 
     EXAMPLE 1 
     Calling Party is Known and Public 
     FIG. 5 is a chart showing the call flows to a subscriber when the subscriber has subscribed to a privacy screening service, and the calling party is known (i.e., it is in the system&#39;s database) and is public (i.e., there are no restrictions on disclosing the name and number to a called party that has, e.g., caller ID). The sequence is also illustrated in FIG. 2 (call  1 , query  2 , response  3 , call  1 ′). 
     As shown in FIG. 5, the call flows start in step  501 , with the calling party dialing the subscriber&#39;s telephone number. That call (call  1  in FIG. 2) goes through the calling party&#39;s SSP (SSP  103 ), carrying with it the calling party&#39;s number 111-111-1111 in the CgPN field, the subscriber&#39;s or called party number 222-222-2222 in the CdPN field, the calling party&#39;s number in the charge number field, and leaving the ReDirectID field blank. The presentation indicator is set to public. In step  502 , SSP  103  routes the call to the subscriber&#39;s SSP (SSP  104 ). When the call reaches SSP  104 , it hits a termination attempt trigger (or TAT) that has been provisioned on the subscriber&#39;s line at is SSP  104 , to provide the subscriber with the privacy screening service. Thus in step  503 , SSP  104  sends a TAT query (query  2  in FIG. 2) to SCP  107 . In step  504 , SCP  107  checks the presentation indicator in the Calling Party ID and determines that the calling party information is not restricted, i.e., is public, and authorizes termination of the call (response  3 ). 
     In step  505 . SSP  104  terminates the call to the subscriber, providing the subscriber with the calling party&#39;s number (and name if the subscriber&#39;s service provides name as well as number). In step  506 , the call goes through (call  1 ′ in FIG.  2 ). 
     EXAMPLE 2 
     Calling Party is Known and Private 
     FIGS. 6-6 a  are charts showing the call flows to a subscriber to a privacy screening service, when the calling party is known, but his/her number is private. In step  601 , the calling party starts the call sequence by dialing the subscriber&#39;s number. The call goes to the calling party&#39;s SSP (SSP  103 ), which routes the call in step  602  to the subscriber&#39;s SSP (SSP  104 ). Because the subscriber&#39;s line at SSP  104  is provisioned with a TAT, this call triggers a TAT query (query  2 ) from SSP  104  to SCP  107  in step  603 . In step  604 , SCP  107  checks the presentation indicator in the calling party ID field and determines that the calling party&#39;s number is private. SCP  107  then toggles the calling party&#39;s presentation indicator from “private” to “public”, and instructs SSP  104  to send the call to SN  109 , with instructions to SN  109  to play an announcement to the calling party, and collect one digit in response. 
     In step  605 , SN  109  plays an announcement (e.g., announcement  93 ) asking the calling party to agree to have his or her number (and name) disclosed to the subscriber. In step  606 , the calling party can respond by, e.g., pressing “1” to agree or “2” to refuse, and SN  109  collects the digit pressed (e.g., the 1 or the 2). If the calling party refuses permission, in step  607 R SN  109  responds by disconnecting the call. In that case, the subscriber never knows that an attempt was made to call him or her. 
     If the calling party agrees to have his or her privacy overriden, in step  607 A SN  109  dials a CDP code Y, the 10-digit called party number and the 10-digit calling party number (call  4  in FIG.  2 ). In step  608 , SSP  108  responds to the CDP code by sending an info_analyzed query (query  4 ′) to SCP  107 , populating the “Access Code” and “Collected Digits” fields as follows: 
     Access code=Y (* 95 , in this example) 
     Collected Digits=the remainder of the digits, i.e. the 10-digit called party number followed by the 10-digit calling party number. 
     In step  609 , SCP  107  responds with an analyze_route message (response  5 ) to SSP  108 , with the subscriber&#39;s number in the CdPN field, and the calling party number in the CgPN field. SN  109  then dials the subscriber&#39;s number in step  610  (call  6 ). When this call reaches SSP  104 , it triggers a TAT, since the subscriber&#39;s line is provisioned with the TAT for the privacy screening service. In step  611 , SSP  104  sends the TAT query to SCP  107  (query  7 ), with the calling party&#39;s number in the CgPN field, the subscriber&#39;s number in the CdPN field, and SN  109 &#39;s number in the ChargeN field. In step  612 , SCP  107  recognizes the charge number as SN  109 &#39;s number, and authorizes termination of the call to the subscriber (response  8 ). In step  613 , if the subscriber has caller ID Deluxe, SSP  104  sends a TR- 1188  CNAM query (query  9 , shown only in FIG. 6 a ) to SCP  107 , which responds in step  614  with the calling party&#39;s name (response  10 , shown only in FIG. 6 a ). SSP  108  terminates the call to the subscriber in step  615 , and the call goes through in step  616  (call  1 ′ in FIG.  2 ). 
     EXAMPLE 3 
     Calling Party is Unknown 
     FIGS. 7-7 a  are charts showing the call flows to a subscriber to a privacy screening service when the calling party is unknown (e.g., because the call is coming from outside the network). In step  701 , the calling party dials the subscriber&#39;s number. The call (call  1  in FIG. 3) is routed by the calling party&#39;s SSP  103  to the subscriber&#39;s SSP  104  in step  702 . This call triggers a TAT at SSP  104 , because the subscriber&#39;s line is provisioned with a privacy screening TAT. In step  703 , SSP  104  sends the TAT query to SCP  107  (query  2  in FIG.  3 ). In step  704 , SCP  107  checks the calling party ID and determines that the calling party is unknown. SCP  107  then responds (response  3 ) to query  2  by instructing SSP  104  to route the call to SN  109 , with instructions to SN  109  to play an announcement to the caller. SSP  104  routes the call to SN  109  via SSP  108 . The call reaches SN  109  with the SN&#39;s Multi-Line Hunt Group Number in the CdPN field, and the subscriber&#39;s number in the ReDirectID field. The calling party field is blank. In step  705 , SN  109  plays an announcement, e.g., announcement  91 , asking the calling party to record his or her name. The calling party agrees, e.g., by saying their name, or refuses (e.g., by hanging up) in step  706 . If the calling party refuses to record his or her name, the call is disconnected in step  707 R. 
     If the calling party records his or her name, in step  707 A SN  109  dials CDP code Y, e.g., * 95 , followed by the subscriber&#39;s number and the lead number of SN  109 &#39;s Multi-line Hunt Group. In step  708 , this dialed string reaches SSP  108 , and the CDP code Y triggers an info analyzed query (query  4 ) from SSP  108  to SCP  107 , with the “Access Code” and “Collected Digits” fields populated as follows: 
     Access code=Y (* 95 , in this example) 
     Collected Digits=the remainder of the digits, i.e. the 10-digit called party number (the subscriber&#39;s number), followed by the 10-digit lead number of SN  109 &#39;s MLHG. 
     In step  709 , SCP  107  analyzes the string, and returns an analyze_route message (response  5 ) with the subscriber&#39;s number in the CdPN field and SN  109 &#39;s lead Multi-Hunt Group number in the CgPN field. SSP  108  calls the subscriber in step  710  (call  6  in FIG. 3) via SSP  104 , triggering the TAT on the subscriber&#39;s line at SSP  104 . In step  711 , SSP  104  then sends the TAT query (query  7 ) to SCP  107 . This query has SN  109 &#39;s Multi Line Hunt Group lead number in the charge party field. In step  712 , SCP  107  recognizes SN  109 &#39;s number in the charge party field, and authorizes termination of the call (response  8 ). 
     In step  713 . SSP  104  terminates the call to the subscriber, and plays an announcement (e.g., announcement  92 ) that includes playing the recording of the calling party&#39;s name. If the subscriber subscribes to caller ID deluxe, SSP  104  also executes a CNAME query to SCP  107 , to which SCP  107  responds with “Privacy Manager” (or a similar name) as the calling party. In step  714 , the subscriber decides whether to accept or reject the call. If the subscriber rejects the call, SSP  104  plays an announcement to the caller rejecting the call in step  715 R, and the call is disconnected in step  716 . If the subscriber rejects the call, optionally the subscriber may select a simple rejection or a sales call rejection or may choose to forward the call to voicemail. If the subscriber decides to accept the call, the call goes through in step  715 A. 
     The foregoing disclosure of embodiments of the present invention and examples of how the present invention can be carried out has been presented for purposes of illustration and description. It is not exhaustive or intended to limit the invention to the precise forms disclosed herein. Many variations and modifications of the embodiments and examples described herein will be obvious to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims appended hereto, and by their equivalents.