2.5 mm headset jack

[Guest kwandds]

what's the difference between a 2 and 3 band headset jack? can you use a two band headset where you normally plug a three banded headset plug?

[Guest Snooginsguy]

what's the difference between a 2 and 3 band headset jack? can you use a two band headset where you normally plug a three banded headset plug?

<{POST_SNAPBACK}>

The third ring is for the microphone. Therefore, you can use a two ring headphone-only jack just fine, you just won't have the option for a microphone. I use a 2-ring 2.5mm - 3.5 mm jack to hook regular headphones up when i'm at the gym, and it works fine.

[Guest Sgt_Strider]

The third ring is for the microphone.  Therefore, you can use a two ring headphone-only jack just fine, you just won't have the option for a microphone.  I use a 2-ring 2.5mm - 3.5 mm jack to hook regular headphones up when i'm at the gym, and it works fine.

<{POST_SNAPBACK}>

Are you sure? Have you tried using the 2 ring version and test if the microphone is disabled? Thanks.

[Guest thenext1]

I've tried a 2.5 to 3.5mm adapter, but the output is distorted and noisy.

I've then tried to plug in my ex-motorola 2.5 headphones, but only the left channel would work.

Anyway, what's the function of the button? It does nothing when idle.... does it answer a call?

[Guest killerost]

If you use a stereo 2.5 mm to 3.5 mm adapter (with two rings), will the phone even recognize that the headset is plugged in??

Here's a simple schematic for a microphone and an answer button. I think this will solve the noise problems you will get when shortcircuiting "Mic" and "Gnd".

Connect a button, a 10 nF capacitor and a microphone parallell.

You can skip the button if you don't need it and the microphone can probably be replaced by a 200-600 ohm resistor.

If the headphones DO work without a microphone, you can just use a little duct tape around the 2.5 mm pin where the third ring (microphone ring) is. Just to avoid the shortcircuit between "Mic" and "Gnd".

Edited March 26, 2006 by killerost

[Guest Snooginsguy]

I've tried a 2.5 to 3.5mm adapter, but the output is distorted and noisy.

I've then tried to plug in my ex-motorola 2.5 headphones, but only the left channel would work.

Anyway, what's the function of the button? It does nothing when idle.... does it answer a call?

<{POST_SNAPBACK}>

Yeah, the button answers calls. It's weird that the Motorola phones don't work, I can't imagine they'd be configured any different than the HTC plugs. I also don't knoow why the sound would be distorted and noisy, unless the adapter is not very good. And to answer Killerost, yes, the phone goes into headset mode with the 2-ring adapter in it.

Again, I have used an adapter with standard headphones many times and have had no problems. I cannot answer a call with the adapter plugged in, though, since the mic on the phone is disabled and my regular headphones have no microphone to use - then I have to simply unplug the adapter and answer it as normal. I do have sound cut out of one of the phones if the adapter is not plugged all the way in, but if I jiggle the adapter a little it clears the sound right up.

[Guest thenext1]

Yeah, the button answers calls.  It's weird that the Motorola phones don't work, I can't imagine they'd be configured any different than the HTC plugs.  I also don't knoow why the sound would be distorted and noisy, unless the adapter is not very good.  And to answer Killerost, yes, the phone goes into headset mode with the 2-ring adapter in it. 

Again, I have used an adapter with standard headphones many times and have had no problems.  I cannot answer a call with the adapter plugged in, though, since the mic on the phone is disabled and my regular headphones have no microphone to use - then I have to simply unplug the adapter and answer it as normal.  I do have sound cut out of one of the phones if the adapter is not plugged all the way in, but if I jiggle the adapter a little it clears the sound right up.

<{POST_SNAPBACK}>

The adapter is what I call a normal adapter, and the earphones were some 3.5 Sony ones previously used in a walkman. And yet the sound had low-volume, and was clicky.

[Guest kam_]

Well its because there are 2 types of headphone/headset wiring. Differential and single ended.

With Differential (Nokia for example) the speakers have a -ve wire and a +ve wire. Neither of these are the same as ground.

Similarly the Mic has a -ve wire and a +ve wire.

It may just look like there's no common ground and tying the two -ve lines together will create one - but in fact it will unbalance the amplifiers in the phone.

Differential is used particularly for GSM phones because its ALOT less suceptable to interferance at 217Hz caused by bursts of GSM frames. The idea of course is that both lines have similar impedance, and run physically close to each other. Interferance is then likely to affect both lines in the same way and the difference in voltage between them is likely to remain identical. With one line being grounded this isn't true anymore. One line is heavily loaded compared to the other and so the interferance affects each line differently.

Anyway if you see a 4 section connector on a headset for a phone with one headphone, its most likely using differential inputs, i for the speaker one for the mic (like nokia and ericsson)

If you see a 4 section connector on phone headphones with no mic, then it could be using differential OR single ended.

If you see a 4 section connector on a phone headset with 2 headphones and a mic then its using single ended.

Of course there are 5 connector inputs too, which most definately are using differential inputs.

The cap or resistor (a mic or speaker acts like a resistor too) is used to sense if the headset is connected only on some phones. It's not always needed.

The 'button' usually shorts two differential inputs and the drop to ground edge is detected by the phone.

You can figure out whats going on with a voltmeter between each input and a point you know is really ground - like the -ve battery terminal

[Guest dishe]

Ok, so explain this one, guys:

Someone told me that his T-mobile SDA (us version) worked with the internal mic when he had headphones plugged in using a 2.5-3.5mm adaptor.

I said that was rediculous, how would the phone know if there was a mic attached?

Then I tried it, and it worked... but only some of the time. I can't figure out what makes it work or not work, but I've noticed that if I boot the phone with a 2.5-3.5mm adaptor and a pair of headphones plugged in, the thing seems to know that there isn't a mic and uses its own (with the audio still coming out of the standard 3.5mm headphones)!

[Guest [email protected]]

If you use a stereo 2.5 mm to 3.5 mm adapter (with two rings), will the phone even recognize that the headset is plugged in??

Here's a simple schematic for a microphone and an answer button. I think this will solve the noise problems you will get when shortcircuiting "Mic" and "Gnd".

Connect a button, a 10 nF capacitor and a microphone parallell.

You can skip the button if you don't need it and the microphone can probably be replaced by a 200-600 ohm resistor.

If the headphones DO work without a microphone, you can just use a little duct tape around the 2.5 mm pin where the third ring (microphone ring) is. Just to avoid the shortcircuit between "Mic" and "Gnd".

[Guest [email protected]]

Gday,

I live in Sydney Australia and I have a question about one of your old posts. You posted the following text (and an attached diagram) in March of 2006:

"If you use a stereo 2.5 mm to 3.5 mm adapter (with two rings), will the phone even recognize that the headset is plugged in??

Here's a simple schematic for a microphone and an answer button. I think this will solve the noise problems you will get when shortcircuiting "Mic" and "Gnd".

Connect a button, a 10 nF capacitor and a microphone parallell.

You can skip the button if you don't need it and the microphone can probably be replaced by a 200-600 ohm resistor."

I am trying to make a cable to connect my Imate Jasjam (mini USB) to a Clearone Chat 50 Audio Conferencing Unit (3.5mm "3 ring" stereo plug) - this is what I have done so far - there were five wires coming from the Imate Jasjam headset cable that I cut in half - (R, L, G, M, S) - they were going to the little inline PCB board with the MIC, Volume Control, and Answer Switch on it -

1) I combined the R-L wires and connected them to the Tip of the 3.5mm connector

2) I connected the M wire to the Ring of the 3.5mm connector

3) I connected the G wire to the Base of the 3.5mm connector

So there is no capacitor or switch as shown in your diagram.

I am getting audio out of the Audio Conferencing Unit fine and the other phone that is calling the Imate can hear when someone talks into the Audo Conferencing Unit - but - when someone talks into the other phone that is calling the Imate - they hear really bad echo - I assume that I have some really bad impedence mismatch somewhere -

I am not an electronics engineer so I do not understand the purpose of the capacitor in your diagram - will a capacitor reduce the echo problem I am having?

Any help or advice would be greatly appreciated,

[email protected].

[Guest G35C]

For those living in the States, check out this store (WMexperts Store). It has an awesome inventory of great quality headphone adapters. Make sure to select Cingular 2125, then click "Headphones". This is the one I bought (Standard Seidio 2in1). I couple it with my Sony MDR-EX71SLA Fontopia Bud-Style Headphones (black to match my Sp5).

Although the final solution is expensive ($30 for adapter + $40 for headphones), it is well worth it in my opinion. The headphones are the Best earbud style you can buy under $40. I do not use the extension that comes with them making the end to end length just perfect! In addition, the adapter has a superb mic , volume control, and call answer/end button.

PS, there are several more adapters on that site in case you don't like mine.

Ka$h