Hi. It is possible that the polarity is reversed in the phone line to the phone. In older phones, the polarity had to be correct for touch-tone to work. What you have to do is to open the phone jack and reverse the polarity. If your jack is modular, that is you plug your phone into it, open the cover and reverse the red and green wires with eachother. This will reverse the line only at this jack. Good luck
slyfox
May 2006