Tech Help PART 4, Installing

Why doesn't my touch-tone phone dial out?

There are several possibilities:

  1. It's defective. (Clues: you don't hear tones or they are "sour", i.e. off-frequency)

  2. Your phone company doesn't provide touch-tone service. (Unlikely, clue: you hear normal touch-tones but you can't "break" dial tone to make a call)

  3. The wires inside your phone -- or phone jack, or somewhere in your house, or outside on a pole or underground or at the phone company -- have "reversed polarity." (Most likely, for an old phone made before about 1985. Clue: when you press a button, instead of hearing a tone you hear a click or a dull "thud.") Open up the phone jack (you may have to temporarily remove it from the wall) and reverse the red and green wires. [See photos.] Some jacks don't have red and green so you may have to reverse the wires in a different-colored pair, usually white with blue stripes and blue with white stripes, or maybe solid blue and solid white. It's quite possible that your phone company has accidentally reversed polarity in the wires feeding your home. You restore touch-tone service by deliberately reversing the accidental reversal, canceling-out the mistake. It's possible, however, that the phone company may make another reversal in the future, usually while splicing a cable, and you may have to reverse your previous reversal. This is why modern touch-tone phones have "polarity guard" circuits.

installing wall phones

Even though almost all phone jacks go on the walls, the term wall jack is reserved for jacks that are designed to support a wall phone.


Wall jacks have either plastic or stainless steel cover plates. The mushroom-like pieces at the top and bottom of a wall jack that fit into holes on the back of a wall phone and support the phone are mounting studs.


The original modular wall phones (middle row, right) had metal backs with slots and modular plugs in them that slid up and down and mated with wall jacks.

Many recent models (bottom row, right — particularly phones that can be used on a table or on a wall — have a jack in their back inside a recessed space, and connect to the wall jack with a short cord that has plugs on both ends.

Some wall phones have short cords that are permanently attached inside the body of the phone.

(above) Some wall phones, particularly convertible models that also work as "desk" phones, come with short cords that connect from the back of the phone to the wall jack. Slots on the back of the phone fit over mounting studs on the jack.