You must select a 2-sided scanning format before sending a 2-sided fax. Select either Long Edge or Short Edge, depending on the layout of your document.
Load your document.
Press . Do one of the following: If your document is flipped on the long edge, press the [2-sided Scan: Long Edge] option.
If your document is flipped on the short edge, press the [2-sided Scan: Short Edge] option.
Press [OK]
Enter the fax number.
Press [Fax Start].