This is the venerable Kenwood TK-790, which was intended for public service/government use. As usual and from the previous link, hams found a way to repurpose them especially since they are well-suited for 9600 baud packet with little modification.

When I got this unit, I immediately removed modified the radio so it didn’t require an external signal for power on and I re-purposed one of the “future use” pins (which lets face it at this point there is no future use for it) for a demodulated output – a modification from TARPN. All of the modifications required are available from the TARPN page.

I have made it work with a Direwolf install, a NucleoTNC, and a AEA PK-232.