# Clear-Com squawk box with Telex Audiocom System



## dumaisaudio (Nov 24, 2009)

I'm using an Telex Audiocom base station, and I'm trying to figure out how I can get a Clear-Com squawk box to work with our system. I borrowed the Clear-Com box from my old University, as we can't afford to buy one right now. My TD says he's pretty sure we can just make an XLR adapter and place the squawk box at the end of the line, because the Telex stuff is balanced and the Clear-Com stuff is unbalanced. I tried searching Google, but am coming up with mostly product pages. Is this possible? If not, is there a way to just wire a speaker up at the end of the line? It's for a trap door op, so he just needs to hear the calls, doesn't need to respond if it comes down to it.


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## Dover (Nov 25, 2009)

There is no way to join the two systems with a physical adapter and maintain the electrical characteristics of each system. There are devices made to do what you want but they are not cheep. However all the Audiocom equipment is Clear-Com compatible, all you need to do is set your Telex power supply to operate in Clear-Com mode and change your belt packs to unbalanced operation. The power supply is simple, it is a little button on the back of the power supply that needs to be pushed with a pen, if there are two switches both MUST BE SET THE SAME. The belt packs are a little bit harder, you need to slide the PCB out and change some jumpers, the settings for which can be found in the manual for the belt pack (it varies by model). You may get more noise in the system as the entire system is now operating on the unbalanced Clear-Com standard but it should still work just fine.

However if I remember right all that happens if you plug a Clear-Com belt pack into a Audiocom system is the call light stays on all the time. 

Can any one else verify this?

Dover


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## Chris15 (Nov 25, 2009)

OK, so if you don't want to go changing every beltpack, you should be able to rig something for the squawk box. Not sure is return audio will work under this scheme, but it ought to...

So this is an adapter...
pin 1 on in and out connected to one another
Audiocom 2 and 3 to the anodes of separate diodes - IN4004 or the like. Common the cathodes and wire to pin 2 for clearcom. This is the power connection.
Audio com 2 and 3 also connect to a 1:1 iso trasformer
The other side of that connects to pin 3 of clearcom and ground.

If things are being a little funky, decouple the audiocom side of the transformer with a cap in each leg.

That SHOULD make it work, but don't hold me to it...


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## museav (Nov 25, 2009)

Telex Audiocom :, Telex's accessory for just this purpose.


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## dumaisaudio (Nov 26, 2009)

Thanks for the posts. As I suspected, the Clear-Com squawk box won't allow me to hook in a headset and talk with the rest of the chain, but it does hear everything that is being said, which serves my purpose just fine. I was getting a slight pulsating sound briefly, but when I adjusted the volume pot, it went away. I still have to put a regular headset down there so the trap op can communicate if something goes wrong, but they don't have to wear a headset now and worry about cables while operating the trap.


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