Q17. We are using multiple fax lines. Can I select a line when transmitting a fax?
Operation procedure
Load the original.
Tap [Scan/Fax] and select a destination.
Tap [Application] and select [Line Setting].
Select a line in [Select Line], then tap [OK].
Press the Start key to start fax transmission.

You can also set a line to use when registering a one-touch destination.