The standard 3.5mm audio mini-jack has been expanded into many uses, including
audio/video equipment and headphones with microphones. These 3.5mm 4-pole
TRS (tip/ring/sleeve) mini-jacks have no standard pinout, so the variations
are plentiful. Here are some of the ones I've come across.
|WD TV Live||Ground||Right||Left||Video|
|Audigy 7.1 audio port 2||Side Right||Ground||Rear Right||Rear Left|
|Audigy 7.1 audio port 3||Side Left||Ground||Subwoofer||Centre|
Some manufacturers just seem to want to make things hard for their customers.
Apple, of course, uses any arrangement, so long as it's non-standard. WD's
tells users that their composite cable is non-standard, but doesn't give
details. It also lies by saying "there will be no sound" if you plug an audio
output device in directly, whereas you'll actually get left channel audio on
the right speaker and hiss (video signal) on the left speaker.