Method and apparatus for screening a call as the call is transmitted to voice mail

A screening and monitoring capability for switch based voice messaging systems that allows a called party to hear the caller and the caller's voice as the caller leaves a message and break in to start a normal telephone discussion if the caller or the caller's subject warrants such action. The method and apparatus of this invention provide for an advanced intelligent network service feature that controls the bridging of the connections to the voice mail and the called party's telephone station. The service feature turns the voice mail off and tears down the connection if the monitoring called party speaks.

TECHNICAL FIELD
 The invention relates generally to voice mail, and more particularly to a
 method and apparatus for screening messages as they are being transmitted
 for storage in a switch based voice mail system.
 DESCRIPTION OF THE PRIOR ART
 As switch based voice mail services have evolved, there is one very
 advantageous service that customer premises equipment answering machines
 provide that switch based voice mail has lacked, namely the ability to
 listen and/or screen a call as a caller stores a message on the storage
 media. By listening and/or screening an incoming call, the called party
 has the option of interjecting himself or herself into the call at any
 time as a message is being stored and talking to the calling party
 immediately if it concerns a matter upon which the called party wishes to
 immediately discuss. This is most useful when family, friends or
 co-workers are traveling and they call from an unfamiliar number, such
 calls cannot be filtered for special attention by their ICLIDs so if the
 called party is busy, calls that the called party would typically answer
 are instead passed to the voice mail system and delayed.
 A switch based voice mail screening service capability has been specified
 generically in BellCore Call Screening Capability GR-1512-Core. But an
 actual embodiment of such a switch based service is not presently
 available.
 Thus, there is a long felt need in the art for a switch based method and
 apparatus for screening voice mail as the voice mail message is
 transmitted by the calling party to the storage medium. Furthermore, there
 is a long felt need for switch based method and apparatus for screening
 voice mail with a capability for interjection by the called party by
 listening and/or speaking to the calling party instead of leaving the
 calling party to transmit a message to the switch based voice mail system
 that will be heard and responded to later.
 SUMMARY OF THE INVENTION
 Briefly stated in accordance with one aspect of the invention the
 aforementioned needs are fulfilled and a technical advance is achieved by
 providing a voice mail screening service using an advanced intelligent
 network (AIN) including a service node connected as a bridging point
 between a calling party, voice mail system, and called subscriber. AIN
 service switching point (SSP) Service Control Point (SCP) is used to route
 the calls to the appropriate location for screening as the calling party
 transmits a message. If the called party is a subscriber to switch based
 voice mail with screening and interjecting capabilities, the called party
 screens the call as the calling party transmits information to the switch
 based voice mail system. Further, the AIN service switching point (SSP)
 Service Control Point (SCP) is used to change the call characteristics,
 such as dialed number, calling number and redirecting number to work
 transparently with existing voice mail systems.

DETAILED DESCRIPTION
 Referring to FIG. 1, an arrangement 10 for a voice mail screening service
 feature is shown. The arrangement 10 has SSP 100. SSP 100 is connected to
 calling party's station 12 through one or more transit switches 20, i.e. a
 public switched telephone network. SSP 100 is connected to called party's
 station 14 and via SSP 200 and transit switches 22 to switch based voice
 mail system (VMS) 500 to which the called party subscribes.
 SSPs 100, 200 and Transit Switches 20, 22 are preferrably connected using
 ISDN User Part (ISUP) Trunks. It is worth noting that SP 100 and SSP 200
 may be the same unit, in which case the ISUP trunk shown between SSP 100
 and SSP 200 is not necessary and only one link to SS7 network 350, instead
 of the two shown in FIG. 1. A service node (SN) 300 is connected to SSP
 200 using either a PRI or a BRI interface. VMS 500 is connected to transit
 switch(es) 22 using as its physical connection a standard voice mail
 interface such as SMDI, but it could also be another interface such as a
 PRI or an ISUP interface.
 In operation, a calling party at station 12 dials the number of called
 party's station 14. The network of transit switches 20 routes this call to
 the called party's switching system 10 causing the called party's station
 14 to ring. If the called party does not answer, switching system 10
 detects a no answer condition and invokes an existing switch feature, Call
 Forwarding on No Answer. The call is forwarded to the number of VMS 500.
 The number of VMS 500 has been provisioned with an AIN Dialed Number
 Trigger (DNT) in the switching system 10. Due to this trigger, an AIN SS7
 query (i.e. Info Analyze Message) is made to SCP 400. This query passes,
 along with other information as specified in BellCore GR-1298, the calling
 party line number, the calling party's number, and the call forwarded
 number. Based on called party's number, SCP 400 determines that the called
 party is a subscriber to voice mail screening service. The SCP 400 returns
 an Analyze Route Message to the SSP 100 indicating that this call will be
 routed to Service Node (SN) 300. The SSP 100 routes the call to SSP 200 of
 SN 300 and passes call setup information over the D-Channel to the SN 300.
 The SN 300 answers the call and stores the calling party's number, called
 party's number and the number of VMS 500.
 Next, SN 300 places a call destined for the VMS 500. In the Setup message
 of the call to VMS 500 SN 300 specifies the calling party with the number
 of the calling party's station 12, the original called party with the
 number of the called party's station 14, and the called party with the
 number of the VMS 500. SSP 200 routes this call to VMS 500, which in the
 example of FIG. 1 crosses transit switches 22, to VMS 500. Then, SN 300
 bridges the call from the calling party at station 12 with the call to the
 VMS 500. The VMS 500 plays the subscriber greeting and begins collecting
 the message from the calling party.
 The called party, who is a subscriber to the voice mail message screening
 service feature, if he or she desires to listen to the calling party
 leaving a message, goes off hook and dials a string, such as *xx, yyyxxxx,
 etc. This string has been provisioned with a trigger (Public Office
 Dialing Plan Trigger or DNT based on the format of the number) in the SSP
 100. This causes an AIN SS7 query (InfoAnalyze Message) to be transmitted
 to the SCP 400. The SCP 400 returns the number of the SN 300 as the
 routing number in an Analyze Info Message response to the query. The SSPs
 100, 200 route the call to the SN 300. The SN 300 answers the call,
 correlates the called party's number with the previous call between the
 calling party at station 12 and the VMS 500. Next, the SN 300 bridges the
 called party on to the call between the calling party at station 12 and
 the voice mail system 500. While the calls are bridged, the SN 300
 monitors the called party's leg of the call for spoken word. If the called
 party speaks, the SN 300 detects it and drops the connection to the voice
 mail system 500. Next, the SN 300 signals to the SSP 200 to bridge the
 call in the switch using a switch capability like the 2 B-Channel Transfer
 Feature.
 If, on the other hand, the called party at station 14 chooses not to screen
 the call, SN 300 detects when the calling party at station 12 or VMS 500
 terminates their leg of the call and tears down the other leg of the call.
 This ends the call initiated by the calling party at station 12.
 Variations
 In another embodiment of the invention, the number used for call forwarding
 is the service node number instead of the voice mail number. In such a
 case, the information delivered to SN 300 does not include the number of
 the voice mail system, therefore the following steps are taken when SN 300
 places the call destined for the voice mail system 500: The SN 300 places
 a call the call for the voice mail leg. A trigger in the SSP 200 such as a
 B-Channel Setup causes an AIN SS7 Info Collected Message to be sent to SCP
 400. Based on the calling party ID parameter which contains the called
 party's (subscriber's) number, SCP 400 determines the VMS 500 number and
 returns an Analyze Information response that includes routing information
 to the VMS 500.
 In yet another embodiment of the invention, after the called party
 subscriber at station 14 has decided to take the call, SN 300 and VMS 500
 can communicate using a protocol such as OCL to remove from VMS 500 any
 partial message left by the calling party.
 In yet another embodiment, after the calling party at station 12 has
 started to leave a message on VMS 500, SN 300 can place a call to the
 called party subscriber at station 14 with a special ringing pattern, e.g.
 a "ping ring", to indicate that the transmission of a message to VMS 500
 is in progress. In such a case if the called party subscriber at station
 14 lifts the handset off-hook, then SN 300 directly bridges the called
 party subscriber at station 14 into the call in screening mode.
 In yet another embodiment, SCP 400 determines whether the calling party has
 finished leaving a message by the use of a Termination message when
 routing the call to SN 300. If the called party subscriber at station 14
 attempts to screen a call to voice mail that has already been completed
 then the calling party subscriber at station 14 is routed to an
 announcement indicating the completion of the previous call.
 In yet another embodiment of the invention, SCP 400 has the capability to
 route to multiple service nodes, i.e. SN 300 and others (not shown). SCP
 400 maintains state on which SN the call from the calling party is routed
 to and routes the screening call from the called party subscriber to the
 proper SN.
 Thus, it will now be understood that there has been described a new method
 and apparatus for screening a call as it is transmitted to a switch based
 voice mail system with the option of the called party to cease screening
 and begin conversing with the calling party of the call. While the
 invention has been particularly illustrated and described with reference
 to preferred embodiments thereof, it will be understood by those skilled
 in the art that various changes in form, details, and applications may be
 made therein. It is accordingly intended that the appended claims shall
 cover all such changes in form, details and applications which do not
 depart from the true spirit and scope of the invention.