The pinout of the microphone connector is as follows:

#1=mike hi  
#2=mike low
#4=handset receive audio
Shell=ground (PTT return)

Note that this pinout is common with this vintage of radio and works with others such as the Motrac.

If you need help getting these radios to go out of band or work in your application, contact Eddie Sinclair at , he seems to be the man with all the answers you'll need.