Brother MFC-665CW - Manual (Page 89)

Control panel setup
82
6
b Press a or b to select LAN.
Press OK.
c Press a or b to select Factory Reset.
Press OK.
d Press 1 for Factory Reset.
e Press 1 for Reboot.
Note
For DCP model, press + for Factory Reset and then press + for Reboot.
f The machine will re-start. You can now reconnect the network cable and configure the network settings
to work with your network.