3 Replies Latest reply: Oct 1, 2007 12:15 PM by Bruce.Ferjulian
Gil Dawson Level 1 Level 1 (80 points)
Does anyone know where to look up the pinout specs for the four-conductor iPhone headset jack?

I would expect left, right, mic and ground for the earbuds, but
(1) which pins carry which signal?
(2) What does the squeeze-switch on the earbud mic connect together?
(3) Would it be OK to Y-connect (i.e., short) left and right for a 3-conductor (audio, mic and ground) mono headset?
(4) I hear reports that people have plugged in stereo headphones after scraping off some plastic for mechanical fit. I expect their headphones would have only 3 connectors (left, right, ground) in a stereo submini (sleeve, ring, tip) configuration. How does this 3-conductor plug work in the iPhone's 4-conductor jack?


12 inch PB G4 w/20 inch Flat Plane Array, Mac OS X (10.4.10)
  • LarksHead Level 2 Level 2 (200 points)
    From my own observations, starting from the tip:

    Tip - Right
    R1 - Left
    R2 - Common
    Sleeve (outer) - Microphone

    The switch appears to short Mic to Common. Inserting a 3-pin plug into the iPhone's 4-pin receptacle would also short Mic to Common. That wouldn't hurt anything and would allow the L/R earphones to work correctly. It also Stops/Starts the iPod, just as the switch would.

    You will not get access to the Microphone without a 4-pin plug.

    I found 4-pin connectors at Arcade-Electronics.Com. The plugs still have to be trimmed to fit the iPhone receptacle. The right-angle plug cannot be trimmed sufficiently.

    Hope this helps.

  • Gil Dawson Level 1 Level 1 (80 points)
    Thanks, Peter. Exactly what I needed.

  • Bruce.Ferjulian Level 1 Level 1 (0 points)
    Perfect. Now all I have to do is find a part ( 3.5mm ) unsoldered plug that is a narrow form factor and I can solder to my old headset or make an adapter.