Set up two-sided Pharos printing in Mac
Sometimes when attempting to print to Pharos printers, the Two-Sided option is grayed out. This happens when installing the Pharos drivers, the Duplex Unit option is not enabled.
Go to System Preferences and choose Printers and Scanners:
Choose the printer and click Options and Supplies
Then click Options:
Click Duplex Unit, then click OK.
Make sure Two-Sided is checked when printing.