Analog differential output (RP, RN, LP, LN). 3034 supports SBC, AAC, APTX, APTXHD. When TWS is used with a box: the highest protocol is APTX. Clear TWS pairing information: the highest protocol is APTXHD (default for 3034). Supports serial port AT commands, 115200, N, 8, 1, supports Android APP to modify Bluetooth name (supports any language), pairing password, custom EQ, switch prompt tone, with call (select in category) Function keys: KCOM, PLAY, VOL+, VOL-, P/V-, N/V+, MODE, high level 3V3 is effective. Control external amplifier mute foot MUTE (with sound: output high 3V3, no sound: output 0V), Bluetooth connection status output foot BT_HL (Bluetooth connected: output high 3V3, Bluetooth disconnected: output 0V) Button Description: "VOL+": short press to increase volume, long press to increase volume; "VOL-": short press to decrease volume, long press to decrease volume; "N/V+": short press to play next song, long press to increase volume; "P/V-": short press to play previous song, long press to decrease volume; "PLAY": short press to play/pause/answer/hang up, long press to reject Special Function Description: "PLAY": long press for 3 seconds and release to force pairing mode, long press for 6 seconds and release to clear pairing list; "PLAY" + "VOL+": long press for 1 second at the same time to enter host mode and search TWS; "PLAY" + "VOL-": Press and hold for 1 second to enter slave mode and TWS is searched; "VOL+" + "VOL-": Press and hold for 1 second to disconnect TWS; "N/V+" + "P/V-": Press and hold for 6 seconds and release at the same time to clear TWS pairing information and pairing password, and reset MODE/TWS key: Bluetooth is not connected to the mobile phone: Short press, host mode search TWS (with prompt sound); Double click, slave mode TWS is searched (with prompt sound); Press and hold for 6 secon