The 2016 Lexmark products no longer support the option for disabling Fax under Function Access Control (FAC). FAC can only limit the access to the fax job icon and panel settings. A new "Disable fax" option is available in firmware version 4.0 (FW4).
A temporary fix is provided in which you access printer’s menu and go to Settings > Fax > Analog Fax Setup. Enter a fax station name and any number, and then uncheck the following:
- Enable Line Connected Detection
- Enable Line In Wrong Jack Detection
- Enable Extension In Use Support