Epson Action Laser II - Manual (Page 219)

The Optional Interface Board
3. Insert the interface board by sliding it along the guides in the
printer. Push firmly on the board until it locks in place.
4. Hand-tighten the screws on the interface board until snug.
5. Turn the printer around. Then attach the proper interface cable
to the computer and to the optional interface connector.
6. Make sure the printer is turned off. Then plug the power cord
into the printer.
Options A-11