Lexmark Optra C710 Setup Manual page 45

Note:
If you align the sides
and front corners of the printer
with the duplex unit base and
then lower the printer, the pins
and connector align easier.
6
Align the pins and connector on top of the duplex
unit base with the holes and connector on bottom
of the printer.
7
Lower the printer onto the duplex unit base.
Installing the duplex unit base
41