help with part identification

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k0ecw
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Joined: Tue Jan 06, 2009 4:54 pm

help with part identification

Post by k0ecw »

I picked up two telephone-type radio handsets at a hamfest. The PTT buttons say "Motorola" on them but every Google search for "Motorola radio handset" or variations thereof haven't been very helpful. I wish to use these handsets with my ham radios and need help identifying just what I have. Ideally I'd like pinouts and/or technical specifications. I don't want to just guess and risk damaging one of my radios.

Here is a picture of the handsets: Image

Any help anyone can offer will be appreciated. Thanks, K0ECW.
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Tom in D.C.
Posts: 3859
Joined: Tue Sep 04, 2001 4:00 pm
What radios do you own?: Progreso soup can with CRT

Re: help with part identification

Post by Tom in D.C. »

You won't be able to make use of these as they are now. Motorola uses special
mic circuitry in their units which requires a voltage, involves a preamp in the mic, etc.
In no particular order here's what I would do with the handset if you want to use it:
1. Unwire the whole unit.
2. Install a PTT circuit on the switch. If the PTT is wired onto/in the mic circuit follow
the manufacturer's diagram; plenty or room inside for small resistors, etc.
3. The earpiece will probably be reusable; if it doesn't work then put in a standard
telephone earpiece. If it's too loud put in a padding circuit.
4. Atlas-Soundolier (now I think known just as "Atlas") probably still makes a direct
replacement insert for the microphone. It's a dynamic rated at 500 ohms and is made
to be installed in a handset. It will work with almost any modern ham transmitter.
Any sound dealer or music shop that does rack work has access to the Atlas line and
can look up the mic unit in the catalog for you.

If you can get a handset hangup unit with a built-in switch you can rewire your speaker
output so the handset audio goes on when you pick up the handset.

One final point. If you find that the element covers can't be unscrewed it means the handsets were intended for use in a prison environment and are virtually worthless, so you should always test handsets to be sure the covers come off before you buy them.
Tom in D.C.
In 1920, the U.S. Post Office Department ruled
that children may not be sent by parcel post.
k0ecw
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Joined: Tue Jan 06, 2009 4:54 pm

Re: help with part identification

Post by k0ecw »

Tom,

Outstanding. Thank you. The covers do screw off so I'm OK there.
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firemedic
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Joined: Sun Sep 09, 2001 4:00 pm

Re: help with part identification

Post by firemedic »

The red unit has a Mostar/MSF5000 base/repeater style plug. I would venture to say it came from a Mostar. The other one is hard to say. We had those here in on our rear control groups for the EMS Micor setups, and on the front controls. Kinda a PIA in an amublance in the front, great in the back of the rig.
Keith Dobbins N8KLD
IT Mainframe Network Engineer
W8TAP Repeater Group
Repeater Technician
Parkersburg, WV
tvsjr
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Joined: Fri Nov 28, 2003 9:46 am

Re: help with part identification

Post by tvsjr »

The one on the right could be for anything as new as a Spectra.
ka8ypy
Posts: 279
Joined: Fri Jan 27, 2006 4:18 pm

Re: help with part identification

Post by ka8ypy »

tvsjr wrote:The one on the right could be for anything as new as a Spectra.
And as old as a PX-300 (or older)
Einstein
Posts: 242
Joined: Tue Feb 21, 2006 4:20 am

Re: help with part identification

Post by Einstein »

TMN6164A Mic Hset for a Quantar
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