6RWH-085
Where to Connect the Telephone Line
Connect the telephone line to the telephone line jack

.
MF746Cx / MF744Cdw / MF645Cx
When connecting an external telephone or an optional handset,

To the jack on the machine
When connecting an optional handset: Connect the telephone line from the handset to the handset jack

on the machine.
When connecting an external telephone or an answering machine: Connect the telephone line from the telephone to the external telephone jack

on the machine.
MF746Cx / MF744Cdw / MF645Cx
If you connect an external telephone with fax functionality, disable the automatic fax receive settings on the telephone.