Motorola mic to kenwood mobile

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Hey all. I have a/an motorola "advanced mobile mic" (HMN4069) that I'd love to use with some ham gear I have (Kenwood TMD700A). I'm attempting to create an adapter from a piece of cat6and am kind of stuck.

I have pinouts for both the Mic and the Radio, but not matter what I do, I cant seem to get the Mic Audio right. I've successfully located/connected the Ground and PTT from the radio to the adapter, and can key/unkey the mic, but cant get any audio into the radio.

I know the mic is good, know the radio is good.

Anyone have any pointers?
 
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Perhaps they don't use the same type of mic elements.

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Well, your kenwood is looking for a 600 ohm connection to your mic. I can't find a lot of info on the motorola mic but being that it is so expensive I would think it would have some extra circuitry inside so that may be why it is not working. If someone has a schematic or can chime in about this microphone I think you may figure out that it may not be possible to do what you want.

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mmckenna

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I believe the Motorola microphones need a bias voltage on the microphone circuit, as they use a mic amp for the condenser microphone elements. Not sure if the Kenwood uses a dynamic microphone. Looking at the pin out for the Kenwood 700, looks like there is an +8vdc supply on the mic jack.
 
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