Saturday | November 17, 2007

The 4th Pin of the Audio Jack

Question of the day: why does the Headphone Jack come with 4 pins?

Posted by mrn at 18:15:43 | Permanent Link | Comments (15) |
Comments
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1 - Because it does video out IIRC. (Comment this)

Written by: Anonymous at 2007/11/18 - 00:48:19
2 - Audio Left, Audio Right, Ground Left, Ground Right. Same as iPod nano. (Comment this)

Written by: Macspotter at 2007/11/20 - 17:05:58
3 - i think...

it needs the "two" grounds to detect if the headphone is plugged in or pulled out.

test for yourself.

play a song and then plug it in / pull out.
the song will stop!

so the pod knows when you do something to the headphone jack.

it has nothing to do with video.

if the two grounds are bridged = headphone in
if the they are open = headphone out
if there is a change of them = stop playing

i think it is as simple as that.

...eok (Comment this)

Written by: eok at 2007/11/20 - 21:38:57
4 - for the iPhone headphones to change (double click) the song and pause and play (single click) with the built in headphone switch/microphone...?
-BJ (Comment this)

Written by: Anonymous at 2007/11/22 - 06:46:34
5 - Has anyone tried the iphone headphones or headphones wiyh a mic on the touch? (Comment this)

Written by: Anonymous at 2007/11/22 - 10:17:23
6 - you are all wrong, its because it is a stereo output. meaning a positive and negative for both left and right. (Comment this)

Written by: Anonymous at 2007/11/22 - 18:23:40
7 - you can have shared ground for both...

The female? The female has video for some devices, but it also can possibly do the pull out thing, but i think thats possible with out this 4 part deal. (Comment this)

Written by: Anonymous at 2007/11/22 - 19:16:51
8 - A bit late, but has anyone checked if the 4th pin is for serial data for like a future remote? (Comment this)

Written by: Anonymous at 2007/11/29 - 08:47:52
9 - Do you suppose it works like the old ipods to output video with one of these?
http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore.woa/wa/RSLID?mco=7E4F2D7D&nplm=M9765G/B
-bryan (Comment this)

Written by: Anonymous at 2007/11/29 - 09:37:59
10 - well... eok has got it right, right?

... can one make an external volume control (tactile, like wheeled ipods)?

a kludgy pause only fix: just cut and rewire an external switch to this jack... (Comment this)

Written by: Anonymous at 2007/11/30 - 23:29:23
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