TAPI 3 Call State event is not firing when device in hands free

Question

I have an application to log call state and call info into a Database table. I use the interop.TAPI3Lib dll and a TAPI3 driver to connect to the call information.

Below is the parts of the code that I think are relevant

I listen for CallState events

tapi.EventFilter = (int)(TAPI3Lib.TAPI_EVENT.TE_CALLSTATE);

tapi.ITTAPIEventNotification_Event_Event += new   
    TAPI3Lib.ITTAPIEventNotification_EventEventHandler(tapi_ITTAPIEventNotification_Event_Event);

And register each device (address) I want to monitor

    RegEventsResult[line] = 
    tapi.RegisterCallNotifications(
    address, 
    true, 
    false, 
    TAPI3Lib.TapiConstants.TAPIMEDIATYPE_AUDIO, 2);

I then log the result of call state changes

private void tapi_ITTAPIEventNotification_Event_Event(TAPI3Lib.TAPI_EVENT TapiEvent, object pEvent)
{
      string callerID, group, extension;
      long origin;
      TAPI3Lib.ITAddress address;

      switch (TapiEvent)
      {
          case TAPI3Lib.TAPI_EVENT.TE_CALLSTATE:

              TAPI3Lib.ITCallStateEvent callStateEvent = (TAPI3Lib.ITCallStateEvent)pEvent;

              TAPI3Lib.ITCallInfo call = callStateEvent.Call;

              extension = call.Address.DialableAddress;

              address = call.Address;

              switch (call.CallState)
              {
                  case TAPI3Lib.CALL_STATE.CS_INPROGRESS:
                            callerID = call.get_CallInfoString(TAPI3Lib.CALLINFO_STRING.CIS_CALLERIDNUMBER);

                            group = call.get_CallInfoString(TAPI3Lib.CALLINFO_STRING.CIS_CALLEDIDNAME);

                            AddLog("InProgress", callerID, group, extension);
                            break;
                  case TAPI3Lib.CALL_STATE.CS_CONNECTED:
                            callerID = call.get_CallInfoString(TAPI3Lib.CALLINFO_STRING.CIS_CALLERIDNUMBER);

                            group = call.get_CallInfoString(TAPI3Lib.CALLINFO_STRING.CIS_CALLEDIDNAME);

                            AddLog("Connected", callerID, group, extension);
                            break;
                  case TAPI3Lib.CALL_STATE.CS_OFFERING:
                            callerID = call.get_CallInfoString(TAPI3Lib.CALLINFO_STRING.CIS_CALLERIDNUMBER);

                            group = call.get_CallInfoString(TAPI3Lib.CALLINFO_STRING.CIS_CALLEDIDNAME);

                            AddLog("Offering", callerID, group, extension);
                            break;
                  case TAPI3Lib.CALL_STATE.CS_DISCONNECTED:
                            AddLog("Disconnected", "", "", extension);
                            resetNotification(extension, address);
                            break;
                  case TAPI3Lib.CALL_STATE.CS_IDLE:
                            AddLog("Idle", "", "", extension);
                            break;
             }
             break;
       }
  }

This works fine - especially as I re-register the device every time it disconnects.

However If the user changes to Hands free on the device - so that calls come through automatically, the call state event does not fire.

If I manually re-register the device during that call, I get a connected call state event.

Any ideas why the device being in hands free would make any difference to the call state event?

Answer 1

I have ended up using TraySoft's AddTapi.Net library, this seems to work very smoothly and is easy to set up and use and documentation is excellent.

And I need to write very little code to achieve the same as above.