I purchased a used iCom comm unit a few weeks ago. I hooked it up to a 12V power supply but aside from the lights coming on and the freqs swapping/tuning, I had no idea if it would work.
So I ordered some jacks, shielded wire, etc., from 'Spruce.
Today I wired up the headphone jack, got out my Lightspeeds, and attached the rubber ducky antenna from my handheld.
Worked great! Picked up DFW tower for arrivals and it came through loud and clear.
I didn't bother checking the TX, because I didn't have a 2nd antenna. But I have no reason to doubt it.