Function description of VHM-314 V.20 version: Compared with the old version, the size is the same, the Bluetooth indicator is blue, and the power indicator is red. VHM-314 V.20 supports Bluetooth 5.0 and lithium battery charging, and adds functions such as keys, dial switches, DIY MUTE interfaces, etc.Product name:MP3 Bluetooth decoder boardProduct number:VHM-314 V.20Bluetooth version: 5.0USB powered:Universal micro-USB 5V power supplyPower supply:3.7~5VSignal to noise ratio:90dbTHD+N: -70dbCrosstalk:-86dbDNR:91dbSupport configuration:A2DP/AVCTP/AVDTP/HFPService Level:Greater than 5 metersVHM-314 V.20 Operating Instructions:Key 1: Short press once is the next song, long press is the volume increase (there will be a "drip" sound prompt at the maximum volume)Key 2: Short press: pause/playKey 3: Short press once for the previous song, long press to reduce the volumePush up switch: Push up to supply power to the battery port. When there is no battery, micro-type supplies power indirectlyPull down switch: micro-type supplies power directly. If no micro-type supplies power, turn off the power.Be Careful:1. The dial switch is fragile. Please protect the switch carefully to avoid damage,2. micro-type indirect power supply may cause noise due to insufficient current supplyColour:blackMaterial:PCB+electronic componentsPackage Contents:2 x MP3 Bluetooth Decoding Board