Epson 1010 User Manual page 169

Note: When you reattach the interface board, rebend the plate
to cover the opening. The plate is sturdy, but be careful not to
subject it to excessive bending.
2. Reattach the board cover.
CAUTION: When an optional interface board is installed,
be sure to disconnect the printer cable from the printer's
built-in parallel interface. Two interface cables must not be
connected at the same time.
Using the Printer Options
5-45