2.3. gc_CallAck( )

The gc_CallAck( ) function allows the application to either:

• send the first response to an incoming call after the GCEV_OFFERED event is received in asynchronous mode or after the gc_WaitCall( ) function returns in synchronous mode
• request additional DNIS (DDI) digits from the network. Using the gc_CallAck( ) function to request additional DNIS digits is described in the GlobalCall API Software Reference.

Note: B channel negotiation is not currently available.

Use the gc_CallAck( ) function when the application is to control sending the Setup or the call Proceeding acknowledgment messages to the network.

When the type field in the GC_CALLACK_BLK data structure is set to GCACK_SERVICE_DNIS, then additional DNIS digits are requested by the gc_CallAck( ) function. When the digits are collected, the gc_CallAck( ) function completes. These digits may be retrieved using the gc_GetDNIS( ) function.

When the type field in the GC_CALLACK_BLK data structure is set to GCACK_SERVICE_ISDN, then the application sends the first response to the incoming call after the GCEV_OFFERED event is received as described below. Controlling the first response to the incoming setup message is optional. Normally, this first response is generated automatically by the firmware. Most applications allow the firmware to handle the first response and thus do not use this feature. If this feature is required, the gc_CallAck( ) function may be used to indicate one of the following conditions to the network:

• the received setup message contains all the information necessary to set up the call. The GC_CALLACK_BLK data structure can be initialized as follows:

         callack.type = GCACK_SERVICE_ISDN;
        callack.service.isdn.acceptance = CALL_PROCEEDING;
        callack.service.isdn.linedev = 0; 
        

• the received setup message contains insufficient destination information. The GC_CALLACK_BLK data structure can be initialized as follows:

         callack.type = GCACK_SERVICE_ISDN;
        callack.service.isdn.acceptance = CALL_SETUP_ACK;
        callack.service.isdn.linedev = 0; 
        

Note: Before using the gc_CallAck( ) function for an ISDN call, the application must use the gc_SetEvtMsk( ) function to enable the application to send the Proceeding message (using the GCMSK_PROC_SEND bitmask parameter).

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