Apple LaserWriter 12/640 PS - Manual (Page 166)

13 Insert the cassette into the printer and the tray into the duplex printing unit.
14 Gently close the duplex printing unit door until it latches into place against the printer. If
the door does not close easily, check to make sure the brace is not locked in place.
15 Reconnect the power cable to the printer and reconnect the printer to the network, then
turn on the printer.
16 Configure your printer to use the duplex printing unit.
For configuration instructions, see “Configuring Your Printer Software for
New Options,” later in this chapter.
For information about printing options,
m see Chapter 6 if you are using the Mac OS
m see Chapter 7 if you are using Windows 3.1 or DOS
m see Chapter 8 if you are using Windows 95
141 Installing Options