Epson LQ-860 User Manual page 189

Attaching the interface board cover
1. Reattach the interface board cover and secure it with the screw
you removed earlier.
2. Replace all parts and options you removed earlier.
WARNING: Before you use the optional interface board, be
sure to disconnect the interface cable for the printer's
built-in parallel or serial interface. Two interface cables
must not be installed at the same time.
5-52 Using the Printer Options