Need Speaker Mic Schematic: CP/GP series

[kf6ywx]

I need the schematic for a speaker mic to fit a GP or CP series radio and cant find squat on the dot com. I've built a pedal switched (PTT) dispatch headset (yes we use handhelds in dispatch...cheap security) which works but has low volume. I suspect that there is a small circuit inisde the mic that provides power to the microphone. I need to replicate this circuit. Thanks