The typical aviation headset features two cords with connectors that at first glance are identical. One is a standard 1/4" (0.25 inch) stereo audio jack.

What kind of connector is the slightly smaller, slightly narrower one?

  • $\begingroup$ Does this answer your question? $\endgroup$
    – fooot
    Jan 25, 2015 at 3:20
  • 1
    $\begingroup$ Totally OT, I know, but I just had a vision of a pilot bopping down the street with his DCs plugged into his phone (via a ¼" to 3.5mm adapter), jammin' to some tunes. Would put those kids with their wimpy Beats™ to shame! $\endgroup$
    – FreeMan
    Apr 8, 2016 at 17:45

1 Answer 1


It's for the microphone (the standard sized one is for the head phones). They are different size so the pilot knows to try the other hole if it doesn't fit.

From wikipedia:

Commercial and general aviation (GA) civil airplane headset plugs are similar, but not identical. A standard 1⁄4 in monaural plug, type PJ-055, is used for headphones, paired with special tip-ring-sleeve, 0.206 inch diameter plug, type PJ-068, for the microphone. On the microphone plug the Ring is used for the microphone 'hot' and the sleeve is common or microphone 'Lo'.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .