Epson EPL-N1600 Reference Manual page 64

4. With the front of the printer towards you, grasp the sides of
the printer. Line up the corners of the printer with the corners
of the duplex unit and place the printer on the duplex unit.
Note:
The printer weighs about 13 kg (about 29lb). Take care when
lifting it, and get another person to help you if necessary.
There are three pins on top of the duplex feeder: two on the left
and one on the right. These three pins fit into three
corresponding holes on the bottom of the printer body for a
secure fit.
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