Xerox DP N24 System Administrator Manual page 261

9 After engaging the closest hook and pin, rock
the Duplex Module forward to engage the
other hook.
11 Close the Duplex Module, snapping it into
place.
10 Attach the safety wire by its hook.
12 Attach the connecting cord to the printer.
Appendix C: Installing and Removing Printer Options
Duplex Module
C-13