The Brother IntelliFax-4100 fax machine has a function called "Sleep" mode. This is a power saving mode which allows the device to remain powered on without using any electricity while it sits idle. You will have to get your IntelliFax-4100 out of this "Sleep" mode before you can use it and take advantage of the various features it provides.
Locate the front control panel on your Brother IntelliFax-4100. This control panel features a series of buttons as well as an LED "Status" screen.
Press the "MODE" button. This changes the mode on the fax machine.
Continue to press mode until it reaches a setting that is consistent with your current setup. If you are using the Brother IntelliFax-4100 on a line by itself, set it to "Fax." If you are using the Brother IntelliFax-4100 on a line that also shares a telephone, set it to "Fax/Telephone." If you are using the Brother IntelliFax-4100 along with an answering machine, set it to "TAD." Once you set your IntelliFax-4100 to the appropriate mode, the unit will leave "Sleep" mode and be ready for use.