Connecting the serial interface (RS-232) cable Be sure to turn off the power supply for both the printer and host computer before connecting the cables. WARNING 1 Insert the serial cable connector firmly into the interface connector. When using connectors equipped with screws, tighten them to secure the connectors firmly. When using interface cables equipped with a grounding line, attach the ground line to the screw hole marked “FG” on the printer. Serial cable 2 Connect the other end of the serial cable to the host computer. 38