Fax TX Line Auto Select Adjustment
You can set whether to automatically select the fax line instead of using the line registered to the recipient, when sending a fax to a destination obtained from a remote address book.
This mode can be set when the Remote Fax function is available for use. For information on the optional products required to use the Remote Fax function, see "Optional Products Required for Each Function."
1.
Press 
(Settings/Registration).
(Settings/Registration).2.
Press [Set Destination] → [Acquire Remote Address Book] → [Fax TX Line Auto Select Adjustment].
3.
Press [On] → [OK].
Select [Off] if you do not want to automatically select adjustment for Fax TX Line.