Motorola Mic wiring

Nickdap · Post by **Nickdap** » Sun Feb 24, 2002 3:32 am

Hi there,
I just picked up a white (with black grile)motorola classic type mic (if you get me). The rj 45 on the end has been removed and im presented with 6 wires, black, red, green, yellow, white and blue. I would like to use this mic on a non-mot rig. which wires are the PTT, GND, and mic audio? thanks for the help. By the way, on connection of the red and black wires to a multimeter and a push of the ptt, i get a reading of around 650 ohms.
Thanks nick

<font size=-1>[ This Message was edited by: Nickdap on 2002-02-24 06:44 ]</font>

Twisted_Pear · Post by **Twisted_Pear** » Sun Feb 24, 2002 5:56 pm

This is coming from a Spectra so things may be different as I don't have anything to check against.

Black = Mic Lo
Red = Mic Hi
White = Dig Gnd
Blue = Hub
Green = PTT
Yellow = Unused

Though most of these jive with my MCS2000 mic.

bls106 · Post by **bls106** » Sun Feb 24, 2002 8:29 pm

be careful on what you try to use the motorola mic on. Most radios out there are 'low impedence'. Motorola mic's are 'high impedence'.

Hope that it works for you. good luck.

Nickdap · Post by **Nickdap** » Mon Feb 25, 2002 4:05 am

Thanks guys, doesnt look to be working for me. cant detect the ptt when its depressed. ohh well not to worry. can you open these up? doesnt really look like it.
thanks again
nick

Post by **wavetar** » Mon Feb 25, 2002 12:45 pm

Sounds like you have an "HMN1035C" or equivalent Maxtrac/GM series microphone. Any made in the last several years are the sealed type, and I haven't found a way to open them without destroying the mic housing. You will not detect the PTT line going to ground, as it's not a simple direct short when you depress the PTT button. It grounds through a transistor circuit, using voltage coming in off the "Mic Hi" lead. Leave it to Motorola to design something complicated when something simple would do the trick!

Todd

Nickdap · Post by **Nickdap** » Tue Feb 26, 2002 4:38 am

on further thought yeah it seems likly it came from a maxtrac. and yes its seald alright. i had a feeling the big m was going to do it to me again.
thanks for the help
nick

perthcom · Post by **perthcom** » Tue Feb 26, 2002 10:37 am

If the radio uses a high level (pre-amp in microphone) input, then you should be able to use it. I've wired them to GE's, Midlands and other older Motorolas without much problem.

Red = Mic high (must be fed with power though a 600-1.2K ohm resister to filtered B+ to run the pre-amplifer)

Green = PTT (it may be an open collector sink to ground)

Black = Ground

Blue = Hook switch

These colours are from the HMN3008 mic which we use as our common mic, but the colours are fairly standard across Motorola lines.

Good luck
Bruce