The remote buttons interface has been designed to make MXL2/MXG/MXS/MXS Strada use easier when the system buttons can be difficult to push: typically, when the dashboard where the system is installed is too narrow or too far from your reach. Basically, it offers 6 contacts to connect to 6 different pushbuttons. The first four are configured in order to simulate the systems buttons, the fifth is intended to turn ON/OFF the backlight and the sixth for resetting the second odometer. The interface has been designed in order to accept a configuration for changing functionality, in case dedicated features will be required.
More info can be found here