1. Switch the car player mode, such as USB mode, radio mode, AUX mode, etc.
2. Control the music play from USB, SD cards, and Bluetooth
3. In the radio state, you can switch FM channels, set frequencies, etc.
4. Control the volume of the car player, and set DSP parameters, such as EQ parameters, delay parameters, etc.
5. Set the system configuration of the car player, such as date and time, etc.