Epson EPL-6200 Reference Manual page 310

Note:
Also make sure that the two projections on the same panel as the
hook are also securely inserted into their corresponding holes on the
back of the printer. Otherwise, you will not be able to lock the Duplex
Unit into place in the next step.
8. While supporting the Duplex Unit with both hands, open the
Duplex Unit cover, and then secure the unit onto the printer
by pushing the two levers upward and turning them 90°
anticlockwise.
Note:
Press the Duplex Unit against the body of the printer when you turn
the levers to make sure that they actually engage onto the printer.
Installing and Removing Options (EPL-6200 only)
8
8
8
8
8
8
8
8
8
8
8
8
293