[Tom Mariner]
Hello Luke,

Yes, we implemented a portable transmitter the implemented the full AX.25
protocol both in an FM waveform generation into the audio in to a TX chip
and a digital implementation into a frequency pull circuit. The main
challenges were the real time CRC generation and the bit stuffing. We used
a commercial TNC, but could have relatively easily done that end as well.

The part used was a '71, but the same concepts would certainly work in an
'84.

Let me know how you come out with your project.

Tom