By default the unit comes as a DCSBIOS device. If you are not familiar with DCSBIOS please check out the following link
https://dcs-bios.readthedocs.io/en/latest/installation.html
Whilst in DCSBIOS mode the Backlit Brightness is controlled by the Console Panel Rotary in game. This however can be overridden by holding FCS Reset and using the Engine Crank Toggle to increase or Decrease the brightness.
If you wished to have this unit as a HID device, this can be achieved by pushing the MODE Switch to A-G (Bottom Position), Holding the FCS Reset button down and flicking Mode all the way to the top A-A in one Push.
The unit will flash and then function as a USB HID Joystick Controller with 128 buttons. This will work perfectly fine for any game and will require mapping to be done in most games.
Whilst in Joystick mode, you may increase or decrease the brightness only by the above FCS and ENG Crank Method.
If you wish to switch back to DCSBIOS Mode this can be achieved by pushing the MODE Switch to A-A (TOP Position), Holding the FCS Reset button down and flicking Mode all the way to the Bottom A-G in one Push.
The unit will flash and then function through DCSBIOS.
HAPPY FLYING!