This would give 12Vdc to the microphone socket for using a DTMF microphone or modification for using an
electret microphone from a multimedia headset in conjunction with Option PH (headphone Option).
This later mod useful with those who do Amateur contests with the addition of a footswitch for TX.
Note:- A label denoting this mod should be added to the front of the radio, plugging in another microphone
may burn out wires or disable the radio permanently.
Modification to the speaker circuit to add voltage to pin 6 of microphone socket.
a resistor and decoupling capacitor will need to be added to drive the electret microphone.