Decoder Board VHM-314 Bluetooth 5.0 MP3 audio decoder board This is a Bluetooth MP3 decoder card. It has buttons and selector as well as a microUSB power interface and a 3.5mm audio jack interface. Features  Model: VHM-314 Bluetooth 5.0 version. Two-channel audio output. Volume can be adjusted Product name: MP3 Bluetooth Decoder Board Supply voltage: 3.7V ~ 5V Current: 20 mA. Charging current: 300 mA (max).  Power indicator: red. Operating temperature: -25° C.~ 85 Operating humidity: 5% ~ 95% RF. Dimensions: 32 x 30.5 x 7.5 mm. DIP switch  1.Dial-up: current for battery connection. In the absence of batteries, the microphone supplies indirect energy. 2.Dial down: the microphone provides direct energy. If there is no MICRO power supply, turn off the power. 3.The DIP switch is fragile. Please protect the switch during use to avoid damage. 4.Indirect MICRO power supply can cause noise due to insufficient power supply.