Greg:? Thanks for your response.? ? Yes, I am using the dedicated 'packet' 6 pin DIN for all connections. On the "TNC" side of the packet cable I have pinned PTT to DB9 Pin 3, TX Data to Pin 1, RX Data (1200baud) to Pin5, and wrapped the signal and chassis grounds together on Pin 6; I don't hook up the squelch wire, the TNC can be set for software-controlled squelch control which is easier.? ? ?I utilize a DB-9 breakout connector (see below)? for the testing which makes troubleshooting much simpler:

I was unaware that the audio is suppressed on the other jacks if the packet connector is used.? However it does make sense, the external speaker jack also cannot be used if the headphone jack in the front is in use.? There is a workaround for tapping receive audio from the Ring/Sleeve of the "data" jack (Tip is PTT).? When I work satellites I tap audio from the data jack to feed a recording device, it's crude but it works. That said, the tap is a modulated audio signal and more than likely 9600 baud, useless for feeding into the TNC.?
Again, Thanks for your response ....Brian/AA5H