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3.5 Releasing Calls
- In order for AG Access to release a call, both the application and the telephone network must actively release it. The telephone network can disconnect a call at any time, regardless of the call control state.
- After the call is released by both the telephone network and the application, AG Access generates a call released event. Once the call is released, no more DSP-related events will be generated on the port, and the application is eligible to receive and place new calls.
- The next two sections present procedures for both types of call releases.
3.5.1 Telephone-Network-Initiated Release
- Releasing a call in response to a telephone network disconnection follows these steps:
- AG Access detects the telephone network disconnect signal and generates an ADIEVN_CALL_DISCONNECTED event.
All active operations that use DSP resources are terminated, and their DONE events are generated.
Note: After the application retrieves the ADIEVN_CALL_DISCONNECTED event from the driver, AG Access will not allow DSP-related operations to be started on the port until the port re-enters the connected state.
- In response to the ADIEVN_CALL_DISCONNECTED event, the application invokes adiReleaseCall.
- AG Access generates a call released event, ADIEVN_CALL_RELEASED.
- When the application processes the event, its internal state is reset to Idle.
- The application is now eligible to place and receive new calls.
3.5.2 Application-Initiated Release
- To release a call from within an application, the application invokes adiReleaseCall. Note that after the application invokes adiReleaseCall, AG Access will not allow DSP-related operations to be started on the port until the port re-enters the Connected state.
- AG Access executes the telephone network teardown procedure.
- AG Access generates an ADIEVN_CALL_RELEASED event.
- When the application processes the event, its internal state is reset to Idle.
- The application is now eligible to place and receive new calls.
3.5.3 Call Release Parameters
- Most of the parameters that govern call release are specific to the telephony protocol running on the given port. Refer to the documentation for the telephony protocol that your application is using for more detailed information. The telephony protocols that are included with AG Access are documented in the AG Access Function Reference Manual.
3.5.4 Call Release Events
- If the telephone network disconnects a call, AG Access generates an ADIEVN_CALL_DISCONNECTED event. When the application calls adiReleaseCall in response to disconnect or to initiate hang up, AG Access generates an ADIEVN_CALL_RELEASED event.
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