trouble with Comcast voip faxing

I came to these forums looking for answers because my HP OfficeJet 6110 All in One would no longer fax over my new Comcast phone. I tried everything suggested and nothing worked. Frustrated I had the Comcast tech come to my home. He found everything in working order, which meant to him the phone worked, he didn't do faxes, that was my machine. He was nice enough to get out his meters and check over the connections and discovered a 'short' in the phone line leading to the fax. Puzzled, he wondered how that could be, everything worked prior to subscribing to Comcast voip. He wondered if perhaps the phone cord (a 4 wire line) supplied with the modem, (a Motorola SBV5220), was bleeding voltage into the 2 wires needed for my fax machine. He cut off the ends, peeled back 2 of the wires and reconnected just 2 wires into a new connector, and plugged this into the modem and the fax. VIOLA' I CAN FAX! He was right. The amount of speed and power through the modem is far greater than a typical analog phone line. So you might give this a try, it worked without any of the other 'solutions' ie dial 99, use pauses befor and after the first number, slow the baud rate, ( I was told by Comcast that voip is so much faster it isn't measured in baud), and several other ideas I've read about. I hope this helps.