GND and VCC are 12V power supplyUsing TI amp TPA6132,better sound qualityGND and BAT are powered by a 3.7V lithium batteryWith call function,CSR8645 low power consumption, power on the boot,the default volume of the largestOUTL,AGND,OUTR for the balanced output,can be directly connected headphones,amplifiers,audio and other input devicesCOM is the common side of the key,the other end of the key are then VOL+,VOL-, PREV,NEXT,PLYM + and M- is the positive and negative of the microphoneCan be connected at the same time two mobile phones (the only way: boot automatically back to the chain of the final match the phone, the penultimate pair of mobile phone to be manually connected)Colour:greenMaterial:plasticPackage Contents:1 x Receiver Board for Car AudioOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.