Abstract:
An intelligent method is disclosed for handling call redirection to an external service provider (ESP) for subsequent call processing. In one embodiment, a network database ( 30 ) is queried to determine whether the calling party station ( 5 ) has pre-selected an ESP for subsequent call processing. In the event that the calling party station has pre-selected an ESP, the call is automatically redirected to the pre-selected ESP; no caller input is required. If, however, the calling party station has not pre-selected an ESP, an announcement is played to the calling party offering a menu of available ESPs. To accept the offer, the caller must explicitly respond to the offer using, e.g., DTMF signaling. The call is then redirected on a per-call basis in accordance with the calling party&#39;s selection.

Description:
This application claims the benefit of U.S. Provisional Application No. 60/031,486, filed Dec. 6, 1996. 
    
    
     TECHNICAL FIELD 
     This invention relates generally to a method for redirecting calls to an external services provider (ESP) for subsequent call processing and, more particularly, to an intelligent method for redirecting calls to an ESP for the provision of voice messaging. 
     BACKGROUND 
     It is known in the art to provide a variety of call services in addition to basic call completion. One such service is automatic voice messaging in which a call encountering a busy or ring-no-answer condition is redirected to a voice messaging platform where the caller can record a message for the called party. The called party is then provided with a message waiting indicator (MWI) in the form of a stutter dial tone or a flashing light on the called party&#39;s telephone and, the called party, upon detection of the MWI, can dial into the platform to retrieve the recorded message from his/her mailbox. 
     SUMMARY OF INVENTION 
     An exemplary method for redirecting a call involving a calling party station to an external service provider (ESP) for subsequent call processing in accordance with the present invention includes: (1) determining whether the calling party station has pre-selected an ESP for subsequent call processing; (2) if the calling party station has pre-selected an ESP, redirecting the call to the pre-selected ESP; and (3) if the calling party station has not pre-selected an ESP, prompting a calling party at the calling party station to select an ESP and, redirecting the call to the ESP as selected by the calling party. 
     Other and further aspects of the present invention will become apparent during the course of the following description and by reference to the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram illustrating a system architecture implementing the intelligent call redirection feature of the present invention. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings wherein like reference numerals refer to like parts, FIG. 1 is a block diagram illustrating a system architecture implementing the intelligent call redirection feature of the present invention. Although not meant to be limiting, the present invention is described in connection with redirection of a call to an external service provider for the provision of voice messaging. 
     A. Network Architecture Elements 
     1. Signaling System No. 7 (SS7) In the architecture of FIG. 1, end-to-end SS7 connectivity for transmitting out-of-band calling activity is assumed. For example, SS 7  interfaces are provided between: (1) the originating Local Exchange Carrier (LEC) switch  15  and the Originating Switch  25  (OS); (2) the terminating LEC switch  20  and the Terminating Switch  40  (TS); (3) the OS  25  and the TS  40 . The SS 7  network also supports queries and responses between the OS  25  and the Network Database  30 . 
     2. Originating Switch (OS) 
     Upon call initiation, the originating LEC  15  uses the calling party  5  number to determine the automatic number identification (ANI) for the call. The originating LEC  15  then generates an Initial Address Message (IAM) containing the ANI and the calling party number together with any privacy indicators and the dialed number (DN) of the called party station  10 , and sends the IAM to the OS  25  over an SS 7  data link. In the architecture of FIG. 1, the OS  25  is an AT&amp;T 4ESS™ toll switch, the details of which are well known in the art. 
     On each call through the network, the OS  25  queries the Network Database  30  using an SS7 Transaction Capabilities (TCAP) Begin Message to determine both “whether” to offer voice messaging on the call and, “how” to offer it. The TCAP Begin Message contains, among other things: (1) the calling station  5  ANI or calling party number and (2) the dialed number of the called station  10 . 
     3. Network Database 
     The Network Database  30  contains customer-specific data regarding the voice messaging service. This information is used to determine both “whether” to offer voice messaging on the call and “how” to offer it. The Network Database  30  determines whether to invoke voice messaging based on the caller&#39;s service type or the call type (e.g., international calls may not be eligible for voice messaging). The Network Database  30  also determines the service preferences and options of the calling and called parties ( 5 ,  10 ) from the ANI or calling party number and the DN received from the OS and, in so doing, determines “how” to offer voice messaging on the call. 
     In accordance with the present invention, there are two modes of handling call redirection to an ESP such as a voice messaging provider—namely, an automatic mode and an on-request mode. ANIs or calling party numbers which are listed in the Network Database  30  as having pre-selected an ESP (e.g.,  65   a  or  65   b ) for voice messaging (i.e., calling party numbers that have a preestablished relationship with an ESP) are assigned to the automatic mode. The on-request mode is used for ANIs or calling party numbers which have not pre-selected an ESP ( 65   a,b ). In the automatic mode, a Monitoring and Announcement Unit (MAU)  45  (described fully below) monitors call progress signals (e.g., in-band RNA and out-of-band user or network busy). Calls encountering a busy or RNA are automatically redirected to the pre-selected ESP ( 65   a,b ) after the MAU plays an announcement to the calling party  5  (e.g., “To leave a message, please wait.”). Because the automatic mode does not require any caller interaction, it provides rotary dial customers access to an ESP and thus, to call services such as voice messaging. In the on-request mode, upon busy or RNA, the MAU  45  will play an announcement to the calling party offering a menu of available ESPs ( 65   a,b ) (e.g., “To leave a message press 1 for AT&amp;T Messaging, press 2 for ABC messaging, press 3 for XYZ messaging.”). The MAU  45  will then monitor for a response from a caller at the calling party station  5 . The caller can select an ESP (on a per-call basis) by pressing the digit on the touch-tone keypad of his telephone or, alternatively, speaking a digit corresponding to the desired ESP ( 65   a,b ). Entry of an ESP selection digit will initiate call redirection to the desired ESP. 
     Additional service preferences and options include: (1) disable voice messaging (as specified by the calling or called party  5 ,  10 ) and (2) customized rings (the number of rings that defines a RNA condition and is the larger of the value specified by the ANI or the DN, or otherwise a default value). With respect to the disable option, a DN corresponding to a called party station  10  which is not conducive to voice messaging could thus disable voice messaging on all calls made to that number. Examples of such DNs include those associated with payphones, facsimile machines and computer dial-in numbers. 
     If the Network Database  30  decides to invoke voice messaging on the call, it forwards instructions to the OS  25  (via a TCAP Instruction Message) to route the call through the MAU  45 . The Network Database  30  also forwards to the OS  25  via the same Instruction Message: (1) a Redirection Feature ID (i.e., automatic mode or on-request mode); (2) a timer value that corresponds to the number of rings that defines a RNA condition; (3) an ESP identifier (for automatic mode the caller&#39;s pre-selected ESP identifier is returned; for the on-request mode, a “best-guess” {e.g., entirely random} ESP identifier is returned); (4) a Redirection Number (RN) which is used to redirect the call to the ESP; and (5) an indication of which ESPs support voice messaging for calls originating from the NPA-NXX of the caller&#39;s ANI. 
     The OS  25  then sends the information contained in the TCAP instruction message to the MAU  45 , routes the call through the MAU  45  and sets up the call to the TS  40  associated with the DN. 
     4. Monitoring and Announcement Unit (MAU) 
     When the MAU  45  is invoked on a call, the call path is “hair-pinned” through the MAU  45 . As indicated above, the MAU  45  monitors for various in-band triggers such as call progress signals (e.g., user busy or RNA) and entry of DTMF or voice signals by the caller (e.g., entry by the caller of an ESP selection digit from the touch-tone keypad of the calling station  5  or, alternatively, entry by the caller of an ESP selection digit by speaking the digit into the transceiver of the calling station  5 ). The MAU  45  also uses out-of-band message processing for the detection of out-of-band triggers such as call progress signals (e.g., network busy). In response to trigger detection, the MAU  45  plays various announcements (e.g., service offerings) to the caller at the calling station  5 . 
     When a call is hair-pinned through the MAU  45 , the OS  25  actually “sees” two separate calls: (1) an “incoming” call from the calling party  5  to the MAU  45  and (2) an “outgoing” call from the MAU  45  to the called party  10 . The “incoming call” is referred to as the “P1” leg, and the “outgoing call” is referred to as the “P2” leg. 
     Although the OS  25  “sees” two separate calls, the MAU  45  knows that the P1 and P2 legs are tied together. The MAU  45  software has both a “Merge” capability and “Redirect Call” capability. A “Merge” is used to tie together a P1 and P2 leg when both legs are already established. For example, a merge is used to tie together (1) a first call between a calling party  5  and the OS  25  and (2) a second call between the OS  25  and the called party  10 , as soon as the called party  10  answers the call. A “Redirect Call” is used to tie together a P1 leg with a P2 leg which has yet to be established. For example, when a call being monitored by the MAU  45  is to be redirected to an ESP ( 65   a,b ), a Redirect Call is performed. In such instances, the following steps are executed: (1) the outgoing trunk (P2) is removed; (2) the MAU  45  instructs the OS  25  to redirect the call to the ESP ( 65   a,b ); and (3) the MAU  45  is disabled (i.e., the MAU  45  is no longer included in the call). 
     5. Terminating Switch (TS) for the ESP 
     If the call is redirected to an ESP ( 65   a,b ), the TS ( 55   a,b ) for the ESP uses Call Redirection Service over a Primary Rate Interface  70  (PRI) to terminate the call at the ESP. After the calling party records a message and goes on-hook, the network tears down the call path. 
     To initiate call set-up between the OS  25  and the selected ESP ( 65   a,b ), the OS  25  first sends an ISUP IAM message to the TS ( 55   a,b ) servicing the ESP ( 65   a,b ). The TS ( 55   a,b ) then converts the IAM message into a Set-Up message for transmission to the ESP ( 65   a,b ). Signaling between the TS ( 55   a,b ) and the ESP ( 65   a,b ) is via an ISDN D channel. The Set-Up message includes the following information: the ANI, the RN and the DN together with the “reason for redirection” (e.g., no answer or busy). The reason for redirection can be used by the ESP ( 65   a,b ) to vary the timing of message delivery (e.g., if the reason for redirection was busy, the ESP ( 65   a,b ) would want to commence forced delivery sooner than if the reason for redirection was no answer). 
     The ESP ( 65   a,b ) then sends (1) a Call Proceeding message to the TS ( 55   a,b ) which maps the message into a Progress message that is sent to the OS  25  and (2) a Connect message to the TS ( 55   a,b ) which is mapped into an Answer message sent to the OS  25 . The TS ( 55   a,b ), in turn, sends a Connect Acknowledge message to the ESP ( 65   a,b ) which is then prepared to receive the call. Upon receiving an Answer message, the OS  25  cuts-through the call to the TS ( 55   a,b ), and hence, to the ESP ( 65   a,b ), where the caller  5  can record a message for the originally called party  10  number. 
     B. Exemplary Call Flows 
     Three call flow scenarios are presented below: (1) automatic mode voice messaging (pre-selected ESP); (2) on-request mode voice messaging—only one ESP; and (3) on-request mode voice messaging—multiple ESPs. 
     1. Automatic Mode Voice Messaging (pre-selected ESP) 
     a. The OS  25  receives a call from the LEC  15 . 
     b. The OS  25  queries the Network Database  30  (the query message includes the caller&#39;s ANI and the DN). The Network Database  30  contains information about the calling party station and the called party station ( 5 ,  10 ), and retrieves this information using the received ANI and DN, respectively. 
     c. The Network Database  30  determines, based on the caller&#39;s service type and the call type, whether to invoke MAU  45  to assist in redirection to an ESP for subsequent call processing such as voice messaging. If the foregoing indicates that the MAU  45  is to be invoked on the call, the Network Database  30  also determines the preferences and options for the calling and called parties. The following preferences and options are available: (1) Automatic Mode Voice Messaging (ESP pre-selected by calling party); (2) On-Request Mode Voice Messaging (ESP not pre-selected by calling party); (3) Disable Voice Messaging (as specified by the calling or called party); and (4) Customized rings (the number of rings defining a RNA condition as also specified by the calling or called party). 
     d. If the MAU  45  is to be invoked on the call, the Network Database  30  returns a response to the OS  25  which includes: (1) an invoke MAU  45  parameter; (2) the Redirection Feature ID (either automatic or on-request mode voice messaging; as described below, the on-request mode Feature ID may also depend upon whether a single or multiple ESPs are available); (3) the RNA Timer value; (4) the ESP ID (in the Network Database  30 , an ESP ID is associated with every ANI that has pre-selected an ESP. For those ANIs that have not pre-selected an ESP and have not disabled call redirection for voice messaging, the Network Database  30  will return the only available ESP ID in the event that a single ESP is available and a “best-guess” ESP ID in the event that multiple ESPs are available); (5) the Redirection Number (RN) (the Network Database  30  will determine the routing to the ESP based on translations of the NPA-NXX of the dialed number  10 ); and (6) an indication of which ESPs support voice messaging for calls originating from the NPA-NXX of the dialed number  10 . 
     e. OS  25  routes the call through the MAU  45  to the TS  40  and passes the information obtained from the Network Database  30  to the MAU  45 . The MAU  45  saves the following information obtained from the Network Database  30  as per call data: ESP ID, RN, RNA timer value, and indicator of ESP support. In addition, the MAU stores the ANI and Calling Party Number (CPN) with privacy indicators, and the DN. 
     f. If the MAU  45  detects that the call is answered, the MAU  45  instructs the OS  25  to merge the two legs of the call and disable the MAU  45 . 
     g. If the MAU  45  detects in-band ringing, the MAU  45  starts a RNA timer. If the MAU  45  detects in-band/out-of-band user busy, or out-of-band network busy, or the RNA timer expires and the Feature ID indicates “Automatic Mode”, then the MAU  45  plays the Automatic Mode Point of Sale Announcement (POSA). For example: “To leave a message, please wait.” Thus, an automatic mode customer need not enter any digits to effect call redirection. 
     h. If the caller  5  remains on the call after the Automatic Mode POSA is complete, the MAU  45  performs the following steps to redirect the call: (1) passes the RN along with the ANI and CPN with presentation indicators to the OS  25 ; (2) instructs the OS  25  to redirect the call to the ESP platform ( 65   a,b ) using the RN; and (3) instructs the OS to remove the MAU  45  from the call and merge the two legs of the call. In the automatic mode, a built-in delay period between the end of the POSA and the start of rerouting is used to provide the caller  5  with a reasonable period of time in which to decline voice messaging (i.e., to hang up). This delay period also avoids the expense incurred by the network of redirecting the call unnecessarily. 
     i. The OS  25  redirects the call to the appropriate ESP platform ( 65   a,b ) using the RN and passes along the ANI and CPN together with associated privacy indicators and the DN. 
     j. When the TS ( 55   a,b ) serving the ESP platform ( 65   a,b ) receives the call, the TS ( 55   a,b ) sends the ESP platform ( 65   a,b ) an ISDN Q.931 SETUP Message which includes the following information elements: 
     (1) Calling Party Number (CPN)=caller&#39;s ( 5 ) ANI or CPN with privacy indicator 
     (2) Called Party Number (CdPN)=Redirection Number (RN) of ESP 
     (3) Redirecting Number=Originally Dialed Number (DN) and reason for redirection (e.g., no answer, user busy, network busy). 
     k. If the caller ( 5 ) stays on the line, the ESP platform ( 65   a,b ) answers the call. 
     l. Once the call is answered by the ESP platform ( 65   a,b ) (i.e., the ESP platform returns Answer Supervision), the call flow in the Network is identical to a POTS call. 
     m. The ESP ( 65   a,b ) uses the Redirecting Number (the original DN) as the address of the called party&#39;s mailbox and, plays a greeting to the caller. 
     n. After the greeting, the caller leaves a message. 
     o. The platform ( 65   a,b ) notifies the called party  10  that a message is in the called party&#39;s mailbox by a message waiting indicator (e.g., a lamp on the called party&#39;s phone) or via a phone call to the message recipient. 
     2. On-Request Mode Voice Messaging—Only One ESP 
     Steps a-f are the same as for Automatic Mode Voice Messaging. 
     g. If the MAU  45  detects in-band ringing, the MAU  45  starts the RNA timer and begins monitoring for caller  5  entered DTMF or spoken digits corresponding to an ESP ( 65   a,b ). Digit collection is also enabled for in-band/out-of-band busy. An ESP selection digit can be entered by the caller any time after ringing or busy has been detected by the MAU  45  and before answer to immediately redirect the call to the ESP ( 65   a,b ) rather than waiting for expiration of the RNA timer or completion of the POSA (see Step g.′, below). 
     g.′ If the MAU  45  detects in-band/out-of-band busy or the RNA timer expires and the Feature ID indicates “On-Request Mode Voice Messaging—only one ESP”, the MAU  45  plays the On-Request Mode—Only One ESP POSA. The POSA may be, for example, “To leave a message, press or say 1 for AT&amp;T Messaging.” 
     h. If the caller  5  presses or speaks an ESP selection digit, the MAU  45  checks the indicator of ESP support to see if the digit is a valid ESP selection digit. If the caller presses a valid ESP selection digit, the MAU  45  then performs the following steps to redirect the call: (1) passes the RN together with the ANI and CPN with presentation indicators to the OS  25 ; (2) instructs the OS  25  to redirect the call to the ESP platform ( 65   a,b ) using the RN; (3) instructs the OS  25  to remove the MAU  45  from the call and merge the two legs of the call. 
     The remaining steps are the same as for Automatic Mode Voice Messaging. 
     3. On-Request Mode Voice Messaging—Multiple ESPs 
     Steps a-f are the same as for Automatic Mode Voice Messaging. 
     g. Same as for On-Request Mode Voice Messaging—Only One ESP 
     g.′ If the MAU  45  detects in-band/out-of-band busy or the RNA timer has expired and the Feature ID indicates “On-Request Mode Voice Messaging—Multiple ESPs”, the MAU  45  plays the On-Request Mode Multiple ESP POSA. 
     The POSA may be, for example, “To leave a message, press or say 1 for AT&amp;T Messaging, press or say 2 for ABC messaging, press or say 3 for XYZ messaging.” 
     h. If the caller presses or speaks a valid ESP selection digit, as determined by the indicator of ESP support, then one of two scenarios result: 
     (1) if the ESP selection digit corresponds to the ESP ID stored in the MAU  45 , then the MAU  45  performs the following steps: (a) passes the RN together with the ANI and CPN with presentation indicators to the OS; (b) instructs the OS to redirect the call to the ESP platform using the RN; and (c) instructs the OS to remove the MAU  45  from the call and merge the two legs of the call, or 
     (2) if the ESP selection digit does not correspond to the ESP ID stored in the MAU  45 , then the MAU  45  performs the following steps: (a) passes the ANI and CPN with presentation indicators to the OS; (b) instructs the OS to query the Network Database  30  to obtain the RN of the ESP selected and redirect the call; and (c) instructs the OS to remove the MAU  45  from the call and merge the two legs of the call. 
     The remaining steps are the same as for Automatic Mode Voice Messaging. 
     The many features and advantages of the present invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the present invention. 
     Furthermore, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired that the present invention be limited to the exact construction and operation illustrated and described herein, and accordingly, all suitable modifications and equivalents which may be resorted to are intended to fall within the scope of the claims.