Say for example I have these headphones with microphone - https://www.amazon.com/2019-Stereo-Headphones-Samsung-Galaxy/dp/B07TWB1R8B/

How do I know if the headphone jack is OMTP or CTIA?

And which of the two standards is more common for the modern headphones with mic? Should I buy OMTP or CTIA?

In general, telephones work with both OMTP and CTIA headphones, or with just one of them? Are there any telephones that support both types of headphones?

4 Answers 4


According to Linx (a headset expert!), the CTIA standard is used in the USA, Hong Kong and other international markets, while OMTP is used primarily in china. The technical difference is that the ground and mic connections are swapped, with OMTP having the ground connection on the last ring away from the tip.

CTIA plug pin-out

image courtesy of linked site

Reading the questions in the Amazon link provided indicates that the headphones work with Samsung devices, which is referenced in the linked site as well.

If you are USA based, it appears that CTIA is the correct choice.

With respect to your edit and comment, the reversal of the ground and microphone contacts would indicate that only one type of device is going to work with the respective contact configuration. This is not a certainty, but I've not discovered "active discovery" type headphones with microphone connection swapping.

  • Thanks, I just added to this the question: "In general, telephones work with both OMTP and CTIA headphones, or with just one of them? Are any telephones that support both types of headphones?"
    – Joe Jobs
    Jul 9, 2021 at 12:55
  • 1
    @JoeJobs I have noticed some work interchangeably, but I don't believe that's intentional... Jul 11, 2021 at 6:14

To confirm your headset ctia or otmp, you need a multimeter. Checking resistance between left/rigt and Gnd should gives you sth like 8/16/32 ohm(not more than this values) thean you have ctia earphones.



As per this picture top to bottom = MIC at the Top, GND, Right, with Left at the bottom = CTIA

I will refer to them a Top, 2nd, 3rd, Btm respectively. also the measurements I show are from a RIG 300HX (xbox version, Xbox is known to be CTIA, so plugging in and testing your headset(gaming) on an xbox controller may also prove it.

Using a good multimeter, choosing the best range on your meter, for each connection, to find the most accurate answer for each measure.

measure: Top-->2nd = MIC ohm might equal 50-20000 ohms

  • for me:
  • Top-->2nd = 8000 ohms

now measure 3rd-->Btm

  • for me:
  • 3rd-->Btm = 320 ohms,
  • each ear (L&R) should be half, or 160 ohms in my case.

at this point we still do not know which is ground, but what we do have is the total impedance

  • MIC-->Btm = 8160 ohms

so now you will do 2 measurements

  • Top-->Btm
  • 2nd-->Btm

whichever is equal to half of 3rd-->Btm

  • = (3rd-->Btm)/2
  • will be the GND

In my case:

  • 2nd-->Btm = 160 ohms
  • so 2nd=GND meaning I have CTIA

if Top-->Btm = (3rd-->Btm)/2, then you have OMTP

Here are my measurements:

  • MIC-->GND = 8000 ohms
  • L-->MIC-->R = 320 ohms
  • GND-->L = 160 ohms
  • GND-->R = 160 ohms
  • MIC-->GND-->L = 8160 ohms

MIC-->GND-->L means because MIC is connected to GND internal and so to is GND to Left/Right speaker, when can measure across MIC-->L/R to get a max reading.

Your readings may vary, but apply the same math and you should be fine.



Please refer to this [electrical guide][1] in android 3.5mm specification

  1. Ear speaker resistance should be greater than 16 ohms
  2. Mic DC resistance should be greater than 1000ohm [1]: https://source.android.com/docs/core/interaction/accessories/headset/plug-headset-spec#electrical

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