Early touchtone dial pads are "polarity sensitive." This means that the current has to flow in the proper direction through it for it to work. There is, of course, a permanent fix, called a polarity guard, which can be found in the link below. But a simple, inexpensive, and quick fix is to order this set of 2 modular line cords of opposite polarity. One is guaranteed to work; one is guaranteed NOT to work. But hang onto both, since your house's polarity can change without warning if the phone company works on the lines. $5 covers the cost of the 2 cords. Color is standard silver.
