Icom IC-255E

The IC-255E is a pretty bomb-proof FM-only mobile rig. It uses helical filters to protect against intermodulation from other stations and two crystal filters for a sharp IF. It also has RIT which is kind of strange for an FM rig. The IC-255A is pretty much the identical radio configured for USA use (143.800 - 148.195 MHz, 15 kHz steps, and the repeater tone burst board is optional (it was standard for the IC-255E)).

There's a socket on the back with receiver detector audio out, squelch out, signal strength out and microphone in -- this is the perfect rig for packet. There are also a 4-bit parallel control interface, which I found (by chance) documented in the Icom CI-V Manual, of all places. See pages 47 and on. This interface can be used to set the frequency only, as far as I can see.

Goran SM2YER has the manual and schematic for download.