CSR8675 supports , -LL, ATPX-HD. on, the default volume is maximum, just listen to music36-55V supply (compatible with lithium battery supply or 5V supply)VCC and GND are supply pins, L, G, R are connected to the earphoneDCOM is the common terminal of the indicator light, and the other end of the indicator light is connected to LED0 and LED1 respectively.KCOM is the common terminal of the button, and the other end of the button is connected to VOL+, VOL-, PREV, , PLY respectivelyAmplifier board size: 57x33CMKey Description:"VOL+": short press to increase the volume, long press to continuously increase the volume"VOL-": Short press to decrease the volume, long press to continuously decrease the volume"": short press the song"PREV": short press the previous song"PLY": short press to play/pause/answer/ up, long press for 1 second to reject incoming callsSpecial function description:"PLY": long press for 3 seconds to force into pairing mode, long press for 6 seconds to clear the pairing list.Material: PCBcolour: BluePackage Contents:1 x Decoder Board1 x AntennaOnly the above package content, other products are not included.Note: Light reflection 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. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.