Call Related Events

Applications can be notified about immediate call related events that demand special attention on the part of the application. These call related immediate events correspond to certain call phases and allow the application to transmit or receive application defined call instance data. Call instance data can be ASCII or binary data and is generally limited to about 512 bytes of data or less. If you know your network infrastructure can support UDP/IP network fragmenting properly, then there is no limitation on the size of call instance data.

When an application uses these call related events in addition to the supporting "call instance data" API procedures, an application has a mechanism to pass data to the receiving side of a call. Also, the application can pass data to a call endpoint that it is transferring to another location. There are many uses for such data interchange capabilities. One such application of these features would be to support enhanced caller ID features that are above and beyond the underlying protocol capabilities of the media engine.

The following immediate call related events can be processed by application software:

SipOutgoingCallInitializing

SipOutgoingTransferInitializing

SipTransferExecuting
SipIncomingCallInitialized