EG25-G Audio over USB


I am trying to test EG25-G Audio over USB, going through the forums I saw a recommendation to test the voice data on USB1, I followed these steps:-

ATD##; (Dial number)

I do not see anything on the USB1 port, I only receive NO CARRIER when the call is disconnected.

The same thing on the QNavigator software opened the NMEA port on a voice call, could not hear anything, Also tried sending a WAV mono file but nothing on the receiving side.

Any suggestions?