I am having trouble setting up a fax machine for a client. They have Verizon Fios internet/phone service. Originally they have a two line phones system with the second line used as a rollover number in case 1st line is busy. I connected one phone wire to the wall jack and the other to the wall jack both coming from back of the HP office jet 7600. THis allowed me to receive faxes, however the auto answer function would not work. Sending faxes was fine. On the Fax I set up with the same line as the main phone line and plugged into the 1/2 jack in the phone. The problem was the fax hijacked line #2 and calls could not rollover or come into that line. Which number would I be best to set up fax on and what configuration would work. The HP rep also said I should call ISP and get a distinct ring for faxes to co-incide with the same ring on the fax machine. Hope my post makes sense and someone has some ideas. Thanks for any tips.