Getting to the bottom of the headphone standard change away from Symbian's...

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There's an interesting tech piece over at Symbian Developers, provocatively titles 'All About Earphones' - no, not a new Rafe site(!) - looking at the electronic side of the headphone standard change in recent years away from the OMTP standard to the iPhone/Android generation. It seems that it's mainly to do with two of the 3.5mm jack pins getting switched. Audio jack geeks only, but knock yourself out here!

From the piece:

UJNgB9z All about earphones and their compatibility with Symbian phones.
Being a smartphone user, you may have experienced a problem when your earphone broke. Then you go to the shop, find a sweet new earphone with really good look, high quality and microphone. Then you try it on your Symbian phone, only to find out that your phone recognizes it as TV-Out cable and you hear the annoying static sound coming out of the earphones. Well, I know that sucks, it happened to me too. But, why does it happen? Can this be explained? Is it possible to get it working? Well…

Lets first take a look at the TRRS jack diagram. I labelled every pin with a letter for obvious reasons.
nsWOJ5C All about earphones and their compatibility with Symbian phones.
First I will get this out of the way: C and D are always for audio channels, C – for right channel and D – for left one. In Symbian, A – is for ground (-) and B – is for microphone and other features. The reason why other earphones don’t work is because they have A and B connections switched, so B – is for ground and A – is for microphone and button(s).

There's a lot more in the piece, but the gist is above. Personally, I do always try and use the headset that came with a phone, believing that it has been tested to some degree and passed some degree of QA. At least, at the mid-to-top end of the market anyway, with in-ear headphones. I realise that cheaper outer-ear ones can often be atrocious.

See also my own 'salute to Nokia multimedia headsets', which is relevant here.

Source / Credit: Symbian Developers