Telephone System Repair

Although many people have forsaken land lines for cell phones, many homes still rely on a standard telephone system. This Fix-It Guide on telephone system repair tells how a telephone system works, what often goes wrong, how to identify a telephone system problem, and what parts and tools you will need to fix it. It then gives simple step-by-step instructions for how to improve transmitter sound and how to improve receiver sound on a standard phone. See the Cellular Telephone Fix-It Guide for cell phone repair.

How Does a Telephone System Work?

A telephone is a low voltage transmitter and receiver for distributing and reproducing sounds over a distance. A call from a fixed telephone goes through a series of local and main exchanges that route it to the called telephone. The call may be transmitted over metal cables, radio links, fiber-optic cables, or a combination of these components. All together, it’s called a telephone system. A cellular (mobile) portable telephone (see the Cellular Telephone Fix-It Guide) connects by radio signals to a nearby base station, then through telephone lines.

What Can Go Wrong with a Telephone System?

The telephone itself may be defective. The modular jack may be defective. The phone lines inside the house, which may be your responsibility, may be defective; the lines outside the house, which are the telephone company’s responsibility, may be defective.

Fix-It Tip

Check your telephone bill. You may or may not be paying a small monthly charge for wiring service. If so, the telephone company will service all wires in your home’s telephone system including those inside the walls and to the jack. If you’re not paying for this service the company’s not responsible for inside wiring.

How Can I Identify a Telephone System Problem?

  • First, determine if the problem is with an individual telephone or the telephone line. If a phone does not operate at all, unplug it and plug another phone into the jack. If the second phone works, the problem is probably in the first telephone. If the second phone doesn’t work either, plug the first phone directly into the telephone network interface module located outside in the box where the telephone lines enter your home. (If the box where the phone lines enter your home does not have a plug for the telephone, use the phone jack nearest where the lines come into the house). If the phone now works, the problem is inside the house. If the phone still does not work, the problem is in the telephone company’s lines coming to the house. Contact your phone company for repairs.
Telephone System Repair

Wiring a modular telephone jack.

  • If the phone does work when plugged into the telephone network interface module, the problem is between there and the module in the house. Use a screwdriver to remove the covers of both the network interface module and the modular jack, and disconnect the red and green wires. Telephone lines come with an extra pair of yellow and black wires, so substitute yellow for red and black for green at the telephone network interface module and at the modular jack. (If you have a second phone number for your house the yellow and black lines may already be in use.)
  • If you get a continuous dial tone, even when dialing, the red and green wires are probably reversed. Try the following options. If you have the same problem on all your telephones, remove the network interface module cover and switch the red and green wires leading to the phones. If the problem affects only one telephone, use a screwdriver to remove the cover of the modular jack serving that telephone and reverse the red and green wires leading from the jack to the telephone.
  • If there is no sound from a classic telephone headset, you may be able to remedy the problem (see below). Electronic phones are harder to service (sometimes impossible because many are sealed).

Other problems may occur within the telephone itself. Although many telephones can be replaced inexpensively, some problems can be resolved easily by checking connections and settings.

What Do I Need for Telephone System Repair?

Replacement parts are available at electronic and telephone supply stores and larger hardware stores, including online stores. The tools you will need to fix a home telephone system include these:

  • Telephone line tester
  • Screwdrivers
  • Denatured alcohol
  • Emery cloth

Fix-It Tip

If you have many problems with your telephone service, consider purchasing a telephone line tester through an electronic supply store. With it you can easily test the telephone signal at the phone box outside of your house as well as individual lines and jacks within it.

What Are the Steps to Telephone System Repair?

Improve transmitter sound on a standard phone:

  1. Unscrew the mouthpiece cover and lift out the transmitter.
  2. Clean off dirt with a foam swab dipped in denatured alcohol.
  3. Clean metal contacts beneath the transmitter.
  4. Raise the metal contacts slightly with a screwdriver and clean with an emery cloth.
  5. Reassemble the headset and make a call. If poor sound persists, have the phone serviced by a professional or replace it.

Improve receiver sound on a standard phone:

  1. Unscrew the earpiece cover and lift out the receiver.
  2. Loosen terminal screws and remove the wire leads.
  3. Clean the leads and screws with an emery cloth.
  4. Reconnect each wire terminal securely to its screw.
  5. Reassemble the handset. If poor sound persists, have the phone serviced by a professional or replace it.