I have a fax machine that will transmit and not receive. I put my butt set on the line and it rings perfectly. When I dial the Fax from my cell the Fax answers and I hear the tones. It will not sync. I have a Postage meter that I can plug into the same line, and it will not dial out. Postage Meter guy said parity was reversed. I reversed parity, no difference. I do not know what to try next. I moved a fax from a different spot and it worked. Xerox M20i. Any thoughts?