Central control RS232 player key button expansion board

RS232 serial port player supporting button expansion board
Support for expanding 13 buttons,
Support illuminated button control
For example, if I select the "1" key, the "1" key light will be on,
Select the "2" key, the "2" key light is on, and the "1" key light is off

Up to 99 buttons can be extended to control the selection of video media files for playback