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3.2 Telephone Network Events

When performing call control functions, AG Access must process the events that arrive from the telephone network, and in response to AG Access commands. AG Access translates the telephone network events into generic call control events. These telephone network events fall into two classes: informational and transitional. Actual event names for use in C programming are defined in uppercase letters with an ADIEVN_ prefix. Refer to Appendix B in the AG Access Function Reference Manual for a complete listing of events.

3.2.1 Informational Events

Informational events do not require any action by the application. For example, the protocol error event, ADIEVN_PROTOCOL_ERROR, provides information about abnormalities on the line including false seizure, too many incoming digits, or premature answer while dialing. Other informational events are generated only if you enable them by setting them in the eventmask in ADI_CALLCTL_PARMS.
The eventmask parameter in ADI_CALLCTL_PARMS dictates which optional informational call control events are generated. This parameter is discussed in detail in Section 3.4.1.
The informational telephone network events are: AG Access Event Description ADIEVN_CALL_PROCEEDING The destination address has been delivered (outbound only). ADIEVN_REMOTE_ALERTING Ring tone has been received from the telephone network (outbound only). ADIEVN_REMOTE_ANSWERED The call is connected to the telephone network (outbound only). ADIEVEN_PROTOCOL_ERROR Abnormalities present on the line. ADIEVN_SEIZURE_DETECTED The telephone network has seized the line (inbound only).

AG Access Event	Description
`ADIEVN_CALL_PROCEEDING`	The destination address has been delivered (outbound only).
`ADIEVN_REMOTE_ALERTING`	Ring tone has been received from the telephone network (outbound only).
`ADIEVN_REMOTE_ANSWERED`	The call is connected to the telephone network (outbound only).
`ADIEVEN_PROTOCOL_ERROR`	Abnormalities present on the line.
`ADIEVN_SEIZURE_DETECTED`	The telephone network has seized the line (inbound only).

3.2.2 Transitional Events

Transitional events are generated when the call state changes. They are generated because AG Access needs the application to choose an action (e.g., incoming call response) or acknowledge that an application command is proceeding (e.g., placing call).
The following table summarizes the transitional events which comprise the majority of call control functionality: AG Access Event Description ADIEVN_INCOMING_CALL The telephone network is offering a call. ADIEVN_ANSWERING_CALL AG Access is answering the incoming call. ADIEVN_REJECTING_CALL AG Access is not answering the incoming call. This can occur for two reasons: either the application commanded it or the protocol forced it due to an application timeout once the remote side hangs up as a result, the reason in the disconnect event value field is set to rejected. The application must still release the call via adiReleaseCall. ADIEVN_PLACING_CALL AG Access has seized an outbound line and is delivering the destination address. For bidirectional lines, the placing call event guarantees that an incoming call event will not be generated until the call is released. This is called glare resolution. ADIEVN_CALL_CONNECTED Inbound: The telephone network connection is established. Outbound: The telephone network connection is established and any other connection criteria have been satisfied (e.g., voice detected, modem tones detected). ADIEVN_CALL_DISCONNECTED The remote party has disconnected or the telephone network has rejected a placed call (e.g., busy tone detected). The application must still release the call by invoking adiReleaseCall. ADIEVN_CALL_RELEASED The telephone network connection and all the AG Access resources allocated to this call have been released. ADIEVN_CALLS_BLOCKED Call establishment is disabled. Inbound calls are rejected and outbound calls are prevented. ADIEVN_CALLS_UNBLOCKED Call establishment is re-enabled. Inbound calls may be received and outbound calls may be placed. ADIEVN_PLACING_CALL2 The main call was placed on hold and a second call is being placed. ADIEVN_CALL2_CONNECTED The third party has answered the call. ADIEVN_CALL2_DISCONNECTED The third party is unavailable or has hung up. ADIEVN_OUT_OF_SERVICE The line is not available for use. Either the telephone network is blocking calls or the line and associated hardware are not configured properly. ADIEVN_IN_SERVICE The line has returned to normal after being out of service.

AG Access Event	Description
`ADIEVN_INCOMING_CALL`	The telephone network is offering a call.
`ADIEVN_ANSWERING_CALL`	AG Access is answering the incoming call.
`ADIEVN_REJECTING_CALL`	AG Access is not answering the incoming call. This can occur for two reasons: either the application commanded it or the protocol forced it due to an application timeout once the remote side hangs up as a result, the reason in the disconnect event `value` field is set to rejected. The application must still release the call via adiReleaseCall.
`ADIEVN_PLACING_CALL`	AG Access has seized an outbound line and is delivering the destination address. For bidirectional lines, the placing call event guarantees that an incoming call event will not be generated until the call is released. This is called glare resolution.
`ADIEVN_CALL_CONNECTED`	Inbound: The telephone network connection is established. Outbound: The telephone network connection is established and any other connection criteria have been satisfied (e.g., voice detected, modem tones detected).
`ADIEVN_CALL_DISCONNECTED`	The remote party has disconnected or the telephone network has rejected a placed call (e.g., busy tone detected). The application must still release the call by invoking adiReleaseCall.
`ADIEVN_CALL_RELEASED`	The telephone network connection and all the AG Access resources allocated to this call have been released.
`ADIEVN_CALLS_BLOCKED`	Call establishment is disabled. Inbound calls are rejected and outbound calls are prevented.
`ADIEVN_CALLS_UNBLOCKED`	Call establishment is re-enabled. Inbound calls may be received and outbound calls may be placed.
`ADIEVN_PLACING_CALL2`	The main call was placed on hold and a second call is being placed.
`ADIEVN_CALL2_CONNECTED`	The third party has answered the call.
`ADIEVN_CALL2_DISCONNECTED`	The third party is unavailable or has hung up.
`ADIEVN_OUT_OF_SERVICE`	The line is not available for use. Either the telephone network is blocking calls or the line and associated hardware are not configured properly.
`ADIEVN_IN_SERVICE`	The line has returned to normal after being out of service.

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