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CDM1250 and rear second mic(acc port)

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CDM1250 and rear second mic(acc port)

Postby Jtsou » Thu Apr 19, 2018 9:35 am

Simple question, can a Motorola handset telephone style mic be connected to a CDM1250’s accessory port?

It is an older mic and I am not sure of the part number but it was connected to a Maratrac and it has the “v” style plug with 6 pins as well as 2 pairs of wires with a plastic plug on the end. I know some customization will be needed for this to work but I just want to know if it will work before I start cutting. Which pins go where. Thanks!

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Re: CDM1250 and rear second mic(acc port)

Postby Jim202 » Thu Apr 19, 2018 4:48 pm

One problem you can expect to run into is many of the older mics and new ones use the tinsel type wire. It is really hard to solder to. So if your intentions are to cut the connector off and solder the wires to the accessory connector pins, you may have a hard time. The accessory pins are the crimp type, so you may be able to learn how to crimp them and be good to go.

You will probably have to go into the radio programming software and do some settings to get the connections to work. There is gain settings that you might have to play with also. A service monitor will be your friend here in setting the gain settings.

One point to remember is you don't want the gain so high that it picks up a bunch of background noise. One of the tests I try to do is to set the deviation to close talking the mic. Then hold it about 2 feet away and you should barely be able to pick up your normal voice. If you still get a fairly high amount of deviation, the gain is set too high and you need to lower it.

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Re: CDM1250 and rear second mic(acc port)

Postby SteveC0625 » Sat Apr 21, 2018 4:56 am

Once you solder to those pins, you've essentially trashed them for any other use in the future. Better to spend about $10 and get an Accessory Connector kit from Ebay seller mre1032. You won't mess up the pins, and you'll have plenty of wire leads to connect to the tinsel. And you will preserve the resale value of the radio.

Also, I've seen quite a few CDM's and other Motorola rear accessory connector radios where somebody tried to solder directly to the pins and ended up with a blob of solder shorting out two or more pins. It's not worth it.

FWIW, I use those kits on every radio I have for ignition sense, rear mic, and remote speaker. As others here will tell you, a remote speaker greatly improves the sound quality in any install, mobile or fixed, or a Waris mobile.

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Re: CDM1250 and rear second mic(acc port)

Postby chartofmaryland » Wed Apr 25, 2018 4:25 am

The “Spectra” end of the handset you are speaking of which goes into the back of A style control heads may not share the same impedance of the CDM and or maxtrac or similar microphones that can wire in well with a RJ45 biscuit box and proper 16 pin rear accessory kit.

Placed many microphones on the rear accessory for all types of 16 pin radios but had issues when taking “spectra line” products and beating them into a 16 pin world

Better off looking for a handset microphone with the RJ45 end and wiring that in

Doesn’t hurt to try if you want to though

Pay attention to the hair thin wiring as Jim202 pointed out which does not accept solder due to the varnish like coating which is why all of that stranding wire was crimped terminated for the microphone and connector ends

If the lights are out when you leave the station and then come on the second you key up, you know you have enough power.

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