Oki LPR C7500 User Manual page 222

For the duplex unit
PostScript or PCL driver
® ® Printers.
1. Click Start Settings
2. Highlight the printer name and click File then Properties.
3. Click the Device Options tab, check Duplex Option Unit.
PostScript Driver PCL Driver
4. Click OK.
C7100/C7300/C7500 Windows Me/98/95 Printer Drivers • 221