Hi my name is Steve Munoz, I'm with Duncan Business Machines. And I'm going to show you how to hook up a fax machine with a DSL modem. First off you're going to need a splitter and you hook this up to the fax machine. You install it into the line emblem. Then you're going to have your fax, which is coming out of the wall, your fax line. You hook it up and then your modem, this is hooked up to your modem. Hook it up to the back, that's why you need a splitter, and that it. Your modem and your fax machine will both function without any line problems whatsoever. That's how you hook up a modem to a fax.