PL Headset XLR4 to 2.5mm TRS?

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Baylink
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PL Headset XLR4 to 2.5mm TRS?

Post by Baylink » Sun Jan 02, 2011 1:32 pm

Can anyone point me to anything that resembles a specification for the 4-pin side of a PL beltbox? Telex headsets are *really* hard on the ears, and I'd like to build an adapter that would let me use, say, a Panasonic KX-TCA60 -- a cellphone/callcenter headset that uses a standard 2.5mm plug -- instead.

Alternatively, of course, does anyone already sell that adapter? :-)

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NECRAT
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Re: PL Headset XLR4 to 2.5mm TRS?

Post by NECRAT » Mon Jan 03, 2011 12:26 am

Never heard of the adaptor but there are plenty of sources online for Telex pin outs.

Pin 1 - Microphone common
Pin 2 - Microphone “hot”
Pin 3 - Headphone common
Pin 4 - Headphone “hot”


From http://www.telexaudiocom.com/faq.php#3
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Baylink
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Re: PL Headset XLR4 to 2.5mm TRS?

Post by Baylink » Mon Jan 03, 2011 8:38 am

That part I could find, yes.

The part I couldn't find is:

"The headset driver expects to put -40dBm into a 16ohm speaker driver, and the mic input expects a biased carbon microphone designed to drive a 200ohm load, with 5vdc of bias on the line, positive tip."

Or whatever the *actual* answers are to those questions...

I have seen non-manufacturer headsets, and I know that headsets are interchangeable across brands, so I can infer strongly that there *are* known answers to those questions (as well as "can I common the two grounds on the headset connector without coupling transformers?"), but I cannot locate the actual answers.

ETA: Never mind; I just found this over on the ControlBooth forums:
You can't use a cell headset, as you MUST have separate grounds for the earpiece and mic...otherwise the sidetone null won't work properly, and you'll have feedback issues, among other things.

Also, to use some computer headsets (and cellphone headsets, were the separate reference grounds not an issue) you need bias power for the electret mic, which is an optional setting that needs to be changed on the circuit board of the ClearCom pack, or provided in the connector/an adaptor box via a circuit you build.

TheSigma
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Re: PL Headset XLR4 to 2.5mm TRS?

Post by TheSigma » Thu Jan 06, 2011 1:49 pm

http://www.rtstw.com/binary/Handbook%20 ... eering.pdf

This has been an invaluable source of info on PL systems, covers more than just RTS, though don't expect to find deep info on clearcom, there is some though.

IF you have a budget of somesort, jk audio makes some sort of bluetooth adaptor for PL beltpacks, I have only seen ads for it though, never the actual unit. ok so here it is http://www.jkaudio.com/blueset.htm, $250, might be cheaper to buy more comfortable headsets. I hate the cheap clearcom headsets, so I converted one of my RTS Beyer dt-109's over to clearcom pining by an adaptor, now I can use it for both. I find the Beyers to be much more comfy, and you can, if you look hard enough, find nice velour earpads for them (I think they actually make 3 or 4 different types of earpads). That blutooth thingy will let you extend your pl over a cell phone, guess you would need one at the other end. pretty cool device actually. I have never used it though so I'm not giving it a recomendation.

*EDIT*

what PL system are you using? CC? RTS? Audiocom? RTS has all the technical documentation availible for download at rtstw.com. We use CC at work But I own an RTS system that I have been using at church and for freelance work. I personally know more about RTS but that is probably because there documentation is easy to get.

Baylink
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Re: PL Headset XLR4 to 2.5mm TRS?

Post by Baylink » Thu Jan 06, 2011 3:16 pm

Well, my beltpacks are Clearcom RS-5X1's.

I've just figured out that the Panasonic KX-TCA60 headsets I used to use at my last job have 4-wire cables, and common the shields in the 2.5mm TRS plug. They also *appear* to have dynamic mics, though it's difficult to get a proper spec on a $7 headset. :-)

I can pull about a 135 ohm DC resistance across the receiver side, and hear the crackles, but the transmit side is effectively open, which I believe implies that it is in fact electret. Pants.

Thanks for the PDF pointer; I'll check that out.

ETA: And my panel box is a PL Pro, 401 (I think it is). And that Intercom Handbook is *priceless*; *really* great stuff, thanks.
Last edited by Baylink on Mon Jan 10, 2011 8:45 am, edited 1 time in total.

TheSigma
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Re: PL Headset XLR4 to 2.5mm TRS?

Post by TheSigma » Fri Jan 07, 2011 8:03 am

Given the cost and application of that headset, It is probably an electret mic, which require a small voltage to function. I bet you figured that out already though. I believe some of my RTS units can supply this, but it appears from the manuals that your CC will work with only dynamic mics (or if the optional connecter is there, Carbon Mics). At that price I may have to order one to play with. They probably can't handle a high noise environment very well, but for a quiet control room, would be much lighter than a closed ear headset.

TheSigma
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Re: PL Headset XLR4 to 2.5mm TRS?

Post by TheSigma » Fri Jan 07, 2011 10:54 am

http://www.epanorama.net/circuits/micro ... html#basic
this may be useful if you can do DIY electronics. if you have the carbon mic input that may be adaptable as well, carbon mics use a bias voltage also. as I said, i may just have to get one of those headsets and do some experiments. only my RTS MCE-325 station has the ability to directly accept an electret mic.

Good luck.

Baylink
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Re: PL Headset XLR4 to 2.5mm TRS?

Post by Baylink » Fri Jan 07, 2011 8:42 pm

Yeah; ControlBooth had a project on this, too, which I think I linked above, but above is below right now, and I can't see it.

TheSigma
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Re: PL Headset XLR4 to 2.5mm TRS?

Post by TheSigma » Mon Jan 10, 2011 8:28 am

So it did. The control booth post eevntually led to thise site where a guy made soome plantronics headsets work, looks simple enough, might work for yours.
http://www.matgoebel.com/projects

Baylink
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Re: PL Headset XLR4 to 2.5mm TRS?

Post by Baylink » Mon Jan 10, 2011 8:42 am

And, for those following this posting, two additional notes:

Clearcom now sells the RS-601 beltbox, which has electret bias power, *and a 2.5mm jack* built in. $300 at BSW

Also, check out the alternate solution to this problem, the JK Audio Blueset, which has bluetooth on one side, and a 4 or 5 pin, M or F XLR on the other. And not only will it let you hook your earpiece up to your beltbox, you can pair it with a phone instead, and use it to extend your PL via cellphone. This little wonder is only $219, also at BSW (which is the only catalog I have it listed in).

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