5 Pin Microphone lead, PTT...

Anonymous067

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May 31, 2008
Hey.

At a facility I work at (doing nothing related to sound/techy stuff), we have a paging microphone (no...its not at a fast food place, just to clear that one up). We usually have background music playing, but when you push the button on the microphone, the music stops and the mic is all that is active.

I noticed its run with a 5 pin XLR. How is this wired?
I can't tell in the main rack in the office of any sort of device that would be cutting the music out (like a compressor/sidechain type thing...).

Anybody seen this?
 

mbenonis

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I think you'd have to take it apart to see. Best guess is that PTT grounds a pin, but I have no idea why you'd need more than four pins at most (+, -, GND, PTT).
 

PhantomD

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No need to over-engineer this here, for all we know why couldn't it be a passive system?

Five pin XLR, three for the normal mic operation, and two for the audio in which is then internally switched out through the mic output into the OEM designed head unit.

Not sure how well that would work, but hey, it's possible, right? And I even neglect to bring phantom power into it (over 5-pin...hmmm).
 

Chris15

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OK guys, let's not get over complicated here...
pin 1 ground
pin 2 audio +
pin 3 audio -
pin 4 & 5 PTT dry contact.

In 5 pin DIN (also used for the same purpose)1 & 3 are audio, 2 ground and 4 & 5 PTT.

This assuming a Telex or similar gooseneck with base style of mic...

BGM muting probably occurs within the mixer amp (assuming a 71.7 or 100v line system).

Such PTT is also common on fist mics used for evac systems to mute the tones whilst an announcement is made from the EWIS panel...
 

museav

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I agree with Chris, it is most likely a simple contact closure at the mic and since it mutes other audio, probably wired back to a mixer or mixer/amp where the contact closure mutes the background music input.

And five pins instead of four so the control does not share ground with the audio and the contact closure could be used for multiple possible control methods (closure to ground, voltage sensing, TTL logic, etc.) that might be employed by the connected devices.
 

AlexD

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Might be a stupid suggestion but if the single to stop the music is at the mic then you could cut the pins that will be sending that single witch I think might be 4-5 ( I say based on no knowledge of PTT).

BTW. What is PTT?

OH! Push to talk, if there is two pins dedicated for this then I do suspect that one of them will be the single for the cut off. Though this is only if it is happening at the mic instead of happening at the mixer or amp. And there is no way of telling which is witch so this won’t help...

This might help instead. Have you consulted any manuals or searched for details online about the different pieces of equipment. There is probably a way of switching this feature off and it will probably tell you how to do it in the manual. If not then you could always hook up a CD player further down the line to overcome this. Though that will cost you money so consult your manual first.

If the signal to cut the music off is coming from the mic then if the mic cant turn it off your quite screwed. Whats the modle of mic that you have?
If the music stops when you press the button and don’t say anything then it will be the mic that stops the music not the amp or mixer.
 
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Anonymous067

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Alex,

With all due respect, please don't throw unrealistic and solutions that don't make sense on the table...

If you don't have a knowledge of how PTT works, don't answer a thread about it.

A single wire can't just "send" a signal that a mixer can "understand". There has to be a specific signal or type of signal send down the wires (basic circuitry). The microphone doesn't have a brain or computer inside of it.

Alex, do you think I would post a thread and take time replying to it before consulting the manufacture, investigation, and manuals?
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AlexD

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Well if the msuic stops when you are pushing the button (with out talkign through it) then there must be somethign down the line that is knowing that you have pushed the button. The button dosent need to be smart to send a signle...

And you may not have found the manual for the equipment. I know lots of people who if they cant find the manual will just give up there and not look online for one. i dont persnaly know you so i coudlent say if u were one of those people.
 
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Chris15

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I thought Brad and I had reached a conclusion based on both our experiences with these sorts of products.

I also wonder where this idea of wanting to disable the PTT function has come from, I don't recall reading it before Alex brought it up.

You just can't send a signal through a single wire. You have to have a second connection to provide a point of reference for your signal.

I'll put money on the pinout being as I listed it. Get a DMM out and do a continuity check between 4 & 5 with the switch in each position.

Let's not confuse ourselves by throwing in all these ideas, it's a simple contact closure, that's it...
 

museav

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Typically, the fourth and fifth pins are purely for a control signal and not for audio. Ironically, I just happen to be working on a project today that I'm looking at a wireless version of this concept (Shure MX690 or 890 wireless desktop base with the SLX4L receiver). For this application, the mute button on the wireless desktop base does not actually mute the audio but instead provides a +5VDC output across two pins on the receiver when the mic is muted, which I am then taking to a control system and via that to a conferencing DSP with distributed echo cancellation. This allows muting the microphones without interrupting or affecting the echo cancellation and for the tech to view the status of the mics even from a remote location. Just an example of how the control pins can be used for a number of purposes.

FWIW, the SLX4L also has a second logic output that provides a +5VDC output when the estimated battery life on the transmitter is under one hour. I plan to simply have that information available to the touch panel in the system so the tech can easily check battery life if there is a problem but I could have the control system send a text message via the LAN to the tech if they wanted that capability.
 
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Anonymous067

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I thought Brad and I had reached a conclusion based on both our experiences with these sorts of products.

I also wonder where this idea of wanting to disable the PTT function has come from, I don't recall reading it before Alex brought it up.

You just can't send a signal through a single wire. You have to have a second connection to provide a point of reference for your signal.

I'll put money on the pinout being as I listed it. Get a DMM out and do a continuity check between 4 & 5 with the switch in each position.

Let's not confuse ourselves by throwing in all these ideas, it's a simple contact closure, that's it...
Chris,

I have no idea why the idea of disabling the PTT came in, I have no intentions of doing this.

I appreciate the explanations. Thanks CHRIS AND BRAD.
 

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