This is a small adapter to convert CGA or MDA, or EGA if the jumper settings are set right, to the "Configurable" (i.e., VGA etc) inputs on the Extron IN1606 (and similar) video scalers.

For CGA/MGA mode, enable all four inner solder jumpers on the underside of the board.

For EGA mode enable just the outer two solder jumpers.