Hi, I have a TYT TH-9800 (compatible with FT-8900) radio that I'm trying to figure out how to turn the 6-pin RJ-12 jack on the head of the radio into a 3.5 mm jack (with PTT). This is for use with APRS, and a Raspberry Pi. I can't seem to figure out the pinout on it. I did find: http://i.imgur.com/pXv8ixM.png Which looked helpful at first, but once I've connected everything, I can only get the radio to transmit if I connect the lines 6 and 4 to either mic transmit or mic ground on the 3.5mm cable. However, all that I get out of the radio is "dead air". I tried connecting pin 5 to the mic transmit on the 3.5 mm cable as well, with no luck in getting audio to pass through (connected my phone, playing a looped audio clip of me identifying my callsign, and "testing"). I've read that others have had difficulty getting this radio model to connect to a 3.5 mm jack as well- does anyone know of a fix? I'm assuming that I'll have to make some sort of a circuit to accomplish this, but I have no idea where to start. Any help would be appreciated!