# Build a Telex Radio interface?



## ccm1495 (Oct 18, 2011)

I was wondering if anyone thought it would be possible to build an interface between motorola radios and a telex audio com system. The radios are CP100's.

Want to some how mimic this but have the radios built in vox to transmit.
Clear-Com TW47 2-Way Radio/Walkie-Talkie Interface | Full Compass


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## Stookeybrd (Oct 18, 2011)

I just want to confirm this. You want the two-way radios to be able to hear the Com system *and* talk to the Com system?

That would involve two (more likely three) circuits to strip the audio off of the XLR, balance it into the two-way radio, take the signal from the radios and integrate it back into the XLR. Also, unless you want your radios to be in listen only mode, you'll have to build a gate that will shut off the signal going to the radios when the signal on Com drops below a certain threshold.


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## Nelson (Oct 18, 2011)

I don't know about the OP, but that's what I would like to do! We have both a hardwired Telex system and two-way radios (old MT1000s). I would love to have the option to interconnect them. That way, the radios could function like wireless Telex units, supporting two-way communication between wireless and wired systems.


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## Footer (Oct 18, 2011)

Yes, its possible to do, how is the real issue. 

However, our friends at Production Intercom have a great solution: AD913- Production Intercom Inc.

Its something I have wanted to get for my venue for awhile. Anything transmitted on the radio system is put on the com system and if a person on com presses the call button they can speak to the radio system. Pretty cool in my opinion, especially for around 300 bucks.


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## ccm1495 (Oct 18, 2011)

That is pretty much what i would like to do. Im wondering if there is any way that i could use the program in and line level speaker output on one of our base station s to avoid having to build a circuit to pull audio off the telex line. I Assume i probably will need a circuit to isolate the radio.

Hope that clarifies my intent?


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## Nelson (Oct 18, 2011)

I don't know the technical specifics of how audio is carried on our Telex intercom system. I don't know how to best interface with it. You would also need a VOX circuit, but that's not too hard to build. Being a ham operator, I'd enjoy tackling a project like this! For $300, I can probably build what I need once I figure out how to interface with the Telex. Interfacing with a radio shouldn't be too hard. Of course, you would have to give up one of your handhelds or buy an extra to use at the interface point.

To make this work correctly, you would have to make sure that the headset users didn't keep their unit on talk all the time, or the VOX wouldn't release the transmitter. I don't know about your folks, but my crew seems to have a bad habit of leaving the talk button on all the time.


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## Stookeybrd (Oct 19, 2011)

Footer said:


> However, our friends at Production Intercom have a great solution: AD913- Production Intercom Inc.


 
This is exactly what you want to purchase. I'm all for DIY projects, but if you're going to begin to rely on this method to run shows, you have got to have a lot of confidence in your project. I did some quick calculations on the circuits that you'll need to build and the cost of components, project box, power supply and cost of coffee, solder, etc. and came to about $210. 

Try to get your school to purchase it, and suggest it as an alternative to a $15,000 wireless com system.


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## Nelson (Oct 20, 2011)

Yeah, I suppose you are right. For around $400 including shipping, that's not all that expensive.


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## Call911 (Apr 26, 2012)

Footer said:


> Yes, its possible to do, how is the real issue.
> 
> However, our friends at Production Intercom have a great solution: AD913- Production Intercom Inc.
> 
> Its something I have wanted to get for my venue for awhile. Anything transmitted on the radio system is put on the com system and if a person on com presses the call button they can speak to the radio system. Pretty cool in my opinion, especially for around 300 bucks.



We purchased this, only to run into issues. Anyone get it working with a Telex system? I called their support and they claim support only for use with a PI system. Any ideas?


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## cpf (Apr 26, 2012)

Production Intercom is only interoperable with ClearCom. Telex is a different system entirely.


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## ccm1495 (Apr 29, 2012)

You may want to take a look at this telex to production intercom adapter. AD920- Production Intercom Inc.


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