Or you can do what I did. When I had my Optimum installed, I had the guy connect one of the houses jacks to plug into the modem so that all of the jacks in the house are on the optimum line. Now with the Obi, all of the jacks in the house are on Obi. My phone isn't plugged into the obi, that cord that's from the house jacks is. My phone and fax are each separately plugged into regular house jacks.