Epson 1500 - Manual (Page 147)

Note:
You do not have to attach the interface board cover when the
optional interface card is installed.
5. Connect any interface cables you removed.
6. Insert the interface cable(s) into the U-shaped part of one
cable clip. Lift the left side of the printer up slightly. Then
hook the short lip of the clip into the forward slot and push
the bottom of the clip under the printer until it clicks in
place. Repeat this procedure with the second clip and insert
it into the back slot.
7. Attach the panel sticker provided in the PCL5/RITech board
package on the area above the printer’s control panel
display and press it in place.
8. Be sure the power is turned off and then plug the power
cord into an electrical outlet.
Options 5-33