Brother MFC-790CW User Manual page 77

Remote commands
98 Change the Receive Mode
1 Msg Ctr
2 Fax/Tel
3 Fax Only
90 Exit
Operation details
If you hear one long beep, your change has been accepted.
Pressing 9 0 allows you to exit remote retrieval. Wait for the
long beep, then replace the handset.
Receiving a Fax
61
6