Why 3.5mm stereo plug earphone cannot use the mic & control wire?

3.5mm stereo plug with mic have 2 ways: OMTP and CITA, the main difference of two ports are the last two interfaces. The seq. of the CITA are left channel、right channel、ground、mic;and the OMTP are left channel、right channel、mic、ground. Your earphone mic and control wire cannot be used if the 3.5mm plug ways which use in the mobile is different from the earphone. We suggest you compare earphone with mobile plug before buying. Please buy VCOM OMTP and CTIA adapter cable for suitable using if you cannot change the devices. 
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