HP LaserJet 1320 - Manual (Page 68)

b. On the Menu bar, select Printing-Change Setup.
c. On the Installable Options-Change menu, select Duplex Unit.
d. On the To menu, select Installed.
e. Click OK.
Mac OS X
1. Do a File-Print, select Duplex, and select Print on Both Sides.
2. If the Print on Both Sides check box does not appear, perform the following steps:
a. In Print Center (Printer Setup Utility for Mac OS X v10.3), click Printer queue.
b. On the Menu bar, select Printers-Show Info.
c. On the Installable Options menu, check Duplex Unit.
d. Click Apply Changes.
e. Close the menu.
58 Chapter 4 Printing tasks ENWW