Xerox WORKCENTRE 7755 System Administrator Manual page 130

Fax
Type in the fax number of a local fax machine using the touch screen keypad, then touch Add.
3.
Place your documents in the document handler, then press Start.
4.
5. Verify that your documents were received by the local fax machine.
130 WorkCentre 7755/7765/7775 Multifunction Printer
System Administrator Guide