You can change the default setting of the On/Off key to Fax Receive:On so that you can receive faxes when the power key is off. (See On/Off setting .) Fax/Tel mode will work in the following ways.

Fax/Tel mode does not work when the power key is off. The machine will not answer telephone or fax calls and will keep ringing. If you are at an external or extension phone, lift the handset and talk. If you hear fax tones, hold the handset until Easy Receive activates your machine. If the other party says they want to send you a fax, activate the machine by pressing  5 1.