CDM 1250 EXTERNAL MIC

[JD]

Does any one know how to wire in a mic on the accessory connector. I am using a standard CDM mobil mic, pin 3 PTT ,Pin 2 Mic hi, pin 7 ground. The mic will not key the radio .

Thanks.

[ve3nsv]

On the radio side it is -
Pin 7 - Ground
Pin 3 - PTT
Pin 2 - Mic hi

Not positive on the mic but I think -
Pin 4 - Ground
Pin 5 - Mic hi
Pin 6 - PTT

I am 100% on the radio, not on the mic though.

[JD]

Thanks for the info. I was using a standard CDM mic hooked into the accessory jack just as you explained. I was only using the PTT pin 3 and Ground pin 7 for the mic just to test. It woulds not transmit, I connected the Mic HI line pin 2, and the mic works fine.

Did more testing, when you use the mic, the mic hi line must be connected fot the radio to transmit.

I do not have a schematic of the mic, must be some circuit configuration.

Again, thanks for the help.

Do you know if the monitor line can be used for the accessory jack ?

[jackhackett]

IIRC those mics only have a SPST pushbutton for PTT and they use it to activate a transistor circuit powered by the voltage on Mic Hi to key the radio.