Whats your phone sound like? That almost looks like a line noise issue . When i had 56K i would hook a laptop direct to the telco's network interface box which should be hanging on the house somewhere. That can help determine if it's something inside the house or if you got a crap line to the telco. The telco's haven't been the best about line maintenance with all the wireless tech out there , they see it as a waste of money to keep up.