This product be like ordinary MP3 decoder board. (This product without bluetooth calling function,with no power amplifier,only connect to an external amplifier can it use). MODE: TF card and U disk: switching sequence for USBTFBluetoothFMAUX;Only U disk: switching sequence for USBBluetoothFMAUX;Only the TF card: switching sequence for TFBluetoothFMAUX;There is no USB and TF card: switching sequence for FMAUXBluetooth.
