PTT (Push to talk) Help

[ShadowXGold]

I have a racing headset. I took a headset wire (TA5FL / Mini-XLR) and put a TRRS plug on the end so I can use in with my phone.

It works perfect with my friends iphone and someone elses non-iphone.

With MY phone, I have to press the PTT button on top of the headset to use the microphone.

How does push-to-talk work and why does it work automatically on other peoples phones but not mine?

Also, please understand that I am a beginner, so please dumb down the explanation for me to understand. I don't even know what ground MEANS. lol. I'd like to know what to do to make me not have to press the PTT button.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

 

[opc]

What country are the phones made in? Your pin-out is only correct for European and Chinese standard headsets. In North America the standard is to swap the MIC an GND pins around.

Try swapping the MIC and GND pins (reverse the red and black wires) and see if that does the trick.

Cheers,
Owen

 

[ShadowXGold]

That didn't work. OK, let me explain this more.


Here is the wire I am trying to convert. It connects a headset to a Motorola walkie-talkie (2-way radio):

An externally hosted image should be here but it was not working when we last tested it.

To talk, you need to push the button on the walkie-talkie, OR push a button on the top of the headset, OR use VOX (voice activated) mode on the walkie-talkie.



Here is a close up of the 2-pin and what I am told the pin-out is:

An externally hosted image should be here but it was not working when we last tested it.

And here is the mention on Yahoo Answers:
Pinout of a motorola 2 pin connector? - Yahoo! Answers

I have no idea what "paralleling the resistors" means. Could that be my problem?


Here is my deduction of the pin-out of the 2-pin Motorola TA5FL wire:

An externally hosted image should be here but it was not working when we last tested it.

Pin 1 appears unused(?). There is a YELLOWand a BLUEwire that appear to be unused. Perhaps they are for the PTT ??? I connected them to each other and it did nothing. I STILL needed to push the button on top of the headset to talk into my HTC Droid Eris.

I am told that for the iphone:

Tip= Left Audio
Ring= Right Audio
Ring= Ground
Sleeve= Microphone

iPhone Headset Plug | GeekSpeak

And you know what? I did it and it worked PERFECTLY for the iphone. It also worked for an LG Chocolate Touch. No need to push a PTT button.

But I tried it with a HTC Droid Eris and I had to push the PTT on the headset to talk.

Also, if I understand, for every other phone besides iphone, the 2nd Ring is the mic and the Sleeve is the ground. Well, like I said, this worked with all 3 phones (2 non-iphones). I reversed the Ground and Mic and it worked exactly the same with all 3 phones. So I don't understand this at all.

Could someone explain this? Also, could someone explain the 1.5k resistor? Is that my problem; that I don't have one of those?

 

[ShadowXGold]

Bump. Does anyone know WHY I have to press the PTT with the android phone but not with the iphone and the chocolate?

What does the PTT on the headset connect ??? Are there 2 of the wires in the TRRS pin-out that the PTT on the headset is connecting? If so, which ones? I tried shorting every combination of wires and still no push to talk. I had to press the PTT button on the headset.

 

[doctorron]

Telephones are made to be used full-duplex...ie, wo PTT.

 

[doctorron]

Phones are made for full-duplex comms, NOT for ptt (unless its a Nextel or similar).

Remember that if you are using PTT you will have more wires...at the very minimum a left, right, common ground for all, and a mic. The PTT is performed on-board the phones.

What Id try is testing continuity across the wires in question and see if it changes when the button is pushed.

As far as the resistor goes, yes, that may be a problem. I'm no EE but perhaps the resistor is used to help pull something low. I don't think so though. I think its to maintain impediance.

BTW, "parallel resistors" are just resistors that branch out from one point onto onr or several points in a circuit. Like this:

-----.-----.-----.-----
| | |
z z z
z z z
| | |
-----.-----.-----.-----

In that circuit up there your resistance is 1/R1+1/R2+1/R3.

Let me study the input of your phone and I'll figure it out. I need OS version, the Eris model (they make a few Eris phones...the same but slightly different) and the brand of headphones. I can do the rest!

Hope I was SOME help...but I doubt it.

DocRon

 

[doctorron]

On the HTC Eris it looks like either the PTT is triggered by a digital pulse down 3&4 simultaneously or is triggered by a resistance change between 3&4 (likely). With no button pushed impediance bet 3&4 should be 47kOhm, but with button pressed should drop to 1 Ohm. You can try a 1 ohm resistor in the wiring for 3&4 BEFORE it goes into the phone...this will pull the impediance into range and the PTT should be gone. Personally, I'd wire the resistor to a SPST switch so you can switch it out if you need to. Good luck! Oh, and as I'm not an EE this may be totally wrong. Check this page out:

HTC HD2, 7 Trophy / Spark, Aria, Arrive, AT&T Desire, Desire (CDMA), Droid Eris, DROID Incredible 2, Droid Incredible ADR6300 , EVO 4G, EVO Shift 4G, Freestyle, Google Nexus One GSM, HD7, Hero GSM, Imagio / XV6975, Inspire 4G, Merge, Mytouch 3G 1.2,

 

[knight27243]

I'm actually trying to do the exact opposite as the OP. I am trying to rig up a PTT for an iphone wherein my throat mic headset will have a button to activate the mic only when I want to talk. i just cant quite get it figured out and can find no other resources online from anyone who has attempted the same.