3.5mm audio interface type description

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3.5mm audio interface type description [Copy link]

【Background description】

Sometimes when we plug non-original headphones into a mobile phone or computer, we find that the sound quality is very poor or only part of the audio is heard. This is mostly because the audio interface types of the headphones and the device are different.

Interface type

The common headphone jacks nowadays are all 3.5mm audio jacks, which are divided into 3-pole and 4-pole. The 4-pole is further divided into Standard and OMTP. This is how Americans call it. In China, OMTP is generally called the national standard, while Standard is called CTIA or American standard. Generally speaking, the plastic ring on the Standard model headphone plug is white, while the plastic ring on the OMTP model plug is black. See the picture below:

Among them, the 3-pole interface, as the name implies, has only 3 contacts on the plug, from the tip to the root, they are the left channel, the right channel, and the power ground, so the headphones with this connector do not support microphones. The 4-pole interface supports microphones, but it can be clearly seen from the above picture that the microphone contacts and the power ground contacts of the Standard and OMTP plugs are in the opposite positions. This is why when we plug the OMTP plug headset into the Standard interface, the sound sounds abnormal, but it is fine when we press the call button on the headset.

However, some electronic devices now have earphone type detection chips added to their circuits, such as ts3a227e, which can automatically detect the type of earphone interface. On such devices, the above three types of earphones can be used normally. If your device does not have this function, you should just change a pair of earphones.