Epson LX-810 User Manual page 183

Interface Boards
FG wire not attached
1. Use the CG screw to attach the round end of the FG wire to
the main board and position the other end as shown.
2. Carefully insert the pins on the optional interface board into
the mating connector on the main board; then secure the board
with the three screws provided.
Using the Printer Options 5-51