Gets a numeric identifier (sequence number) of the call.
A numeric identifier assigned by the telephony system to this call.
Some telephony systems can assign a unique identifier to each call.
This allows the call to be tracked across transfers, redirects, or other events.
If this feature is not supported, the CallID property is zero for all calls.
Assembly: Traysoft.AddTapi (Module: Traysoft.AddTapi)