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?

I've not looked at your code in detail, but be aware of talking directly to TAPI from .NET. The garbage collector and auto-generated COM interop layer don't play nicely with it, and while it looks like it's working, you do run into strange issues now and again. There are 3rd party libraries around that properly expose TAPI to .NET, or you can go the approach of writing a C++/CLI wrapper yourself. Good Luck! — James Thorpe, Aug 26 '16 at 16:14

score 2 · Answer 1 · answered Aug 31 '16 at 14:10

This "Hands free" mode should not be affecting the events you get. I recommend you use a independent tool to check if other applications get the same result. Because you may have found a bug in your driver or PBX. If you don't have one, you can try the TAPI soft phone here:

http://julmar.com/tapi/

Also re-registering after every call should not be necessary and may actually do more harm then good.

score 0 · Accepted Answer · answered Sep 02 '16 at 15:25

0

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.

answered Sep 02 '16 at 15:25

Peter Campbell

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

2 Answers2