A note on headset standards: OMTP, AHJ and Apple

alv3st3r

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There are different types of headsets and they are not compatible with each other. The most common issue that causes compatibility issues is the number of conductor points on the headset and what they are connected to, but the signalling arrangement (i.e. the way remote controls work) is also important.

Modern smartphone typically use headsets with four conductor points (the "bands" that you can see on a connector). In almost all cases two points are used for audio out (stereo), one for the microphone, and one for signalling (e.g. to end a call). However, these points are not always used in the same way, or in the same order.

There are two common arrangement for a four conductor point headset. The first, known as American Headset Jack (AHJ) standard, has the microphone connector point on the sleeve end, with the signalling (or ground) connector on the second ring. This arrangement is used by HTC devices, and some recent devices from Sony and Nokia. Apple uses a similar connector arrangement, but uses a non-standard microphone and control signalling method.

The second common arrangement is the longer established and more formalised OMTP standard. It has the signalling connector (ground) next to the sleeve, with the microphone connector on the second ring. This is the reverses of the AHJ arrangement. It is used by the majority of mobile phones currently being sold, most Samsung smartphones, and older Sony Ericsson and Nokia smartphones.

Plugging an OMTP headset into an AHJ jack, and vice versa, will result in the audio-out being inaudible or very quiet. Converters to switch between the two types of headsets are readily available, but do add extra bulk, and may not work reliably with remote control functionality.

headset.jpg

All HTC Windows Phone devices uses the AHJ connector, while Samsung's Windows Phone use the OMTP connector (unconfirmed for the most recent devices as Samsung has started switching over).

Nokia's first generation of Lumia products (Nokia Lumia 505, 510, 610, 710, 800 and 900) have an AHJ connector, which is different from the OMTP connector used in earlier Nokia products (including its Symbian smartphones). Note that Lumia 620 is the only Windows Phone 8 device that uses AHJ connector.

Nokia's Windows Phone 8 devices (Nokia Lumia 520, 521, 720, 810, 820, 822, 920, 925 and 928) use a new universal connector, enabling the use of both AHJ and OMTP headsets.

Apple's non-standard signalling and control method means many designed for iPhone headsets are incompatible with other devices. In general the audio out and one button control on such headsets will work, but the audio-in (microphone) and volume controls will not. Some headset manufacturers produce dual version products that have wider support (presumably supporting more than one signalling method), but working out which is which is a little hit and miss. Its advisable to avoid iPhone specific headset accessories where possible; instead look for AHJ or OMTP compatibility as suited to your specific device.

An added complication is added in by the way in which the signalling (remote control) element works. The AHJ standard has a number of defined shortcuts in addition to the single button press (answer/end call, or play/pause music). These include a long press for voice commands, a double press to skip forward a music track, and a triple button press to skip back a music track. These shortcuts do not always seem to be universally implemented, but there's no particular pattern that can be recognized.

For info on "How to: do more with one and three button headsets on Windows Phone." Click this link.

Source: AAWP and Nokia
 
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alv3st3r

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I've made a few corrections to the Rafe's article. Mods please make this thread sticky. It'll help many users out here and move it to the appropriate section if its posted in the wrong section.
 

ohgood

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One of the things I really like about some firmware versions is negating the need to care about which standard was used, if any:

(Screen off , using the phone volume buttons):

Volume up/down functions normally

Long press volume up/down skips forward/reverse to next song in the current playlist.

The only downside is it means accessibility of the phone, but this works through my winter jackets, so I'm happy.

Even better is customization of what each volume/function key from the ear phones execute on the phone, ex: let the hardware be dumb and the phone be smart.

I gave up on ear buds controls years ago, their life span is too short.
 

Derausgewanderte

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thank you for this summary. Very informative and finally a detailed answer to why my Logitech Ultimate Ears 600vi won't work on my Lumia 920. Until recently (I believe before GDR2) the pause and play button would actually work if I held it long enough. Not anymore though. Now none of the buttons work. No surprise though, as they were specifically designed for i(my fingers don't want to type this).

But it seems there is hope? You write about converters...Wonder if there is a way to fix this with a simple adapter/converter (this has a little diagram what the adapter accomplishes)? Actually, for a few bucks on ebay doesn't hurt to just buy and try.

Not a big deal anyway. I got the Nokia Purity On-Ear Headphones when they were on sale at MS for $50 and I like them (sure, not as good as my Bose, but for 50 I better shut up). Easy to get used to the button controls. I am afraid your answer to my adapter/converter question is a "not possible"...

let me know and thanks again for writing this up.
cheers
 
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alv3st3r

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Glad it helped you. I can't comment on the button controls as the pattern varies from phone to phone. Also I've never used them and to be honest its quite confusing. But I know a guy who can help you in this regard. You can contact him here: In Ear Matters: Contact me :)

I've had a similar connector to what you posted and it didn't last long. I find "just a connector" to be a better solution without the hassle of wire. Something like this: $4.00 - 4 pole 3.5mm Male to Female adapter Convertor for Iphone Nokia Moto handfree - LS001073 -

PS: Did you check this link that I mentioned in the article? It might answer your question.
 

Derausgewanderte

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Update. The adapter I purchased on eBay did not work. Seems to be one way only. The earphones work, but the buttons are still dead. Ah well, was worth a try.
 

Guzzler3

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Apple's non-standard signalling and control method means many designed for iPhone headsets are incompatible with other devices. In general the audio out and one button control on such headsets will work, but the audio-in (microphone) and volume controls will not. Some headset manufacturers produce dual version products that have wider support (presumably supporting more than one signalling method), but working out which is which is a little hit and miss. Its advisable to avoid iPhone specific headset accessories where possible; instead look for AHJ or OMTP compatibility as suited to your specific device.

An added complication is added in by the way in which the signalling (remote control) element works. The AHJ standard has a number of defined shortcuts in addition to the single button press (answer/end call, or play/pause music). These include a long press for voice commands, a double press to skip forward a music track, and a triple button press to skip back a music track. These shortcuts do not always seem to be universally implemented, but there's no particular pattern that can be recognized.
Is there any documentation on the signaling/control impulses for windows phones somewhere?
 

hooddy

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Can someone advice me please, if I open AD-54 (or AD-43) and desolder vice versa Grd and Mic wires from OMTP to AHJ would it works with my Lumia 620 as full features headset (volume control and buttons)?
 
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thundr51

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I know this is (relatively) old but as I just passed some older headphones down to my son and doing a bunch of research to find some 'cans' for myself that work with my 8x or the latest lumias, it seems there are three options.
1. Buy wireless headphones.
+ Bluetooth/NFC standards and protocols seem to be fairly uniform for these types of things. YAY!
- most are very expensive
- sound quality is debatable
2. Buy an I- device and have access to the millions of peripherals created for them
3. Buy what you want and hope that at the very least you can get music out of it

At this point seriously thinking about the Sol Republic track airs as the Nokia Purity pros HD are $300+ and from the most recent reviews say they keep breaking thanks to a little plastic tab.

Update: I finally decided on the Bluedio R+ Legend. I really like all the features (headphones with built in microSD support?! yes please) they came with and I haven't had any problems. I highly recommend them.
 
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Sicarius123

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Has anyone come across replacement cables for the Purity HD/Pro? I'd love to have volume control as well as mic on my headphones with removable cable, no reason why these cables wouldn't work!

Alternatively any other AHJ cables and remotes?
 

AnnoyingCat

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just made myself an inline remote like the one in this link " willrobertson.id , au/projects/htcheadphone/ "
and it doesn't work with my 520 :'(, don't know why but it works just fine on my samsung android.
Not AHJ and OMTP difference, i tried swapping the line already. Help pls? :C
 

Heidi Mueller

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I've made a few corrections to the Rafe's article. Mods please make this thread sticky. It'll help many users out here and move it to the appropriate section if its posted in the wrong section.
I have read both Rafe's article and your note. I need to connect an external mic for video work. Can I use a Rode Smartlav (designed for Apple) with my Lumia 830? Does the "universal" adapter still have mic on the sleeve with power for the mic?
 

Puncher34

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I ordered one of the adapters I found. My general review is "yes, it swaps the necessary contacts." What I didn't realize until now, which is a separate issue, is that the OPO is an *insanely sensitive device* when it comes to headphones, microphones, and controls. I'll begin a fresh thread on that topic. Basically the point here is "there's more than just pinout when it comes to deciding if a headset is going to play nice with your OPO."
 
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