Epson LQ-1050 User Manual page 197

Installing the board
There are two basic types of interface board designs, which slightly
change the way they are installed in the printer. The frame ground
wire is attached for one type and not attached for the other. This
difference does not affect the operation of the interface in any way.
Check to see which type of interface board you have and then follow
the instructions for that type of board.
FG wire
If the FG wire is not attached, follow these steps:
1. Set the DIP switches on the interface board according to the
manual accompanying your interface board. (If you are installing
the #8143 board, see the next section, #8143 New Serial Interface.)
Using the Printer Options
5-48
attached
not
FG wire at attached