Global Call ISDN Technology User's Guide: 3.1. Inbound Calls, Asynchronous Mode

3.1. Inbound Calls, Asynchronous Mode

Table 15 describes the sequencing of function calls and the messages exchanged with the ISDN carrier during an asynchronous mode inbound call. The items denoted by an asterisk (*) are optional functions/events. To prevent interruptions by events that the application does not want to respond to, some events can be masked.

Table 15. ISDN Inbound Call Set-Up (Asynchronous)

Function/Event

Action/Description

gc_WaitCall( ) Issued once after line device opened with gc_Open( ) or gc_OpenEx( ) Incoming calls are unblocked

GCEV_OFFERED Indicates arrival of an incoming call; A Setup message was received from the network;Proceeding message sent to network;

When using Springware boards, by default, the Proceeding message is automatically sent to the network
When using DM3 boards, by default, the application must explicitly use the gc_CallAck( ) function to send the Proceeding message

Note: The application may connect a voice resource channel to the B channel at this time.

gc_GetDNIS( )* Request DNIS information. Information returned is stored in buffer.

gc_GetANI( )* (when using Springware or DM3 boards)OR gc_ReqANI( )* (when using Springware boards only) Information returned is stored in buffer. Request ANI information.

gc_CallProgress( )* (when using Springware boards only) Progress message sent to acknowledge that the call was received. No response expected from network.

GCEV_CALLPROGRESS* Termination event

gc_AcceptCall( )* Alerting message sent to acknowledge that call was received but called party has not answered.

GCEV_ACCEPT* Termination event - indicates call received, but not yet answered.

gc_AnswerCall( )

Note: Application may connect a voice resource channel to the B channel.
Connect message sent to connect call to called party (answer inbound call) Calling party may respond with a Connect Acknowledged message

GCEV_ANSWERED Termination event - indicates inbound call connected Causes transition to Connected state.

* = Optional function/event

Table 15. **ISDN Inbound Call Set-Up (Asynchronous)**
Function/Event	Action/Description
gc_WaitCall( )	Issued once after line device opened with gc_Open( ) or gc_OpenEx( ) Incoming calls are unblocked
GCEV_OFFERED	Indicates arrival of an incoming call; A Setup message was received from the network;Proceeding message sent to network; When using Springware boards, by default, the Proceeding message is automatically sent to the network When using DM3 boards, by default, the application must explicitly use the gc_CallAck( ) function to send the Proceeding message Note: The application may connect a voice resource channel to the B channel at this time.
gc_GetDNIS( )*	Request DNIS information. Information returned is stored in buffer.
gc_GetANI( )* (when using Springware or DM3 boards)OR gc_ReqANI( )* (when using Springware boards only)	Information returned is stored in buffer. Request ANI information.
gc_CallProgress( )* (when using Springware boards only)	Progress message sent to acknowledge that the call was received. No response expected from network.
GCEV_CALLPROGRESS*	Termination event
gc_AcceptCall( )*	Alerting message sent to acknowledge that call was received but called party has not answered.
GCEV_ACCEPT*	Termination event - indicates call received, but not yet answered.
gc_AnswerCall( )	Note: Application may connect a voice resource channel to the B channel. Connect message sent to connect call to called party (answer inbound call) Calling party may respond with a Connect Acknowledged message
GCEV_ANSWERED	Termination event - indicates inbound call connected Causes transition to Connected state.
* = Optional function/event

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