Common Landline Problems and Repairs

There can be minor problems in phone lines that can be fixed by yourself than waiting for the telephone company maintenance which can take time.

Is it just one of several phones that isn’t working? If it is, swap two of your phones. If the trouble moves with the phone, the phone or its cord is defective. If the trouble stays with the particular outlet, the problem is in that outlet or the wires leading up to it.

To repair any problem, you first must establish what you’re up against. Are all of the phones working? Are none of the phones working? What do you hear when you call your number from another phone? Now that you have an idea of the nature of the problem, attempt to sectionalize the trouble. There are numerous places where you can logically separate sections of your phone service. Consider each of these places and ask yourself which side the trouble is likely to be on.

Consider everything connected to your phone line. Often the trouble is in a device you may not think about, since these devices may be out of sight, out of mind. If you all of your phones are dead, disconnect all of these devices as your first troubleshooting step.

The Network Interface Device (NID), also referred to as the Subscriber/Network Interface (SNI) or the Point of Demarcation (Demarc), is the box, often grey and usually on the outside of the structure, where the telephone company’s wires start, the lightning protector is installed, and your phone wiring terminates. (True to telephone company tradition, the terms “NID” and “SNI” are pronounceable acronyms — they are usually spoken as “nid” and “sny” rather than “n.i.d.” or “s.n.i.”) An important feature of the NID is a test jack with a short phone cord. Unplugging this cord disconnects all of your internal wiring from the telephone company’s network, allowing you to plug a “known-good” phone into the NID to verify that the service is working up to your home or business. If it is, your “service” is fine but your wiring or a device inside are causing the problem.

Home and small business phone wiring is usually installed using one of these topologies:

Star or Home Run – each jack has a wire running back to the NID.
Daisy Chain – wires from the NID go from one outlet, to the next, to the next. (This may also be called a “ring” topology, except that it is not a true ring, since the last outlet doesn’t loop around and then go back to the NID.)
Combination of the two – You may find a spur subtending from a point along a daisy chain, or that some outlets have a home run back to the NID while others are part of a Daisy Chain

Line lockout can trip you up when troubleshooting. When your telephone line is left off the hook for more than a couple of minutes, the telephone company may switch automatically places your line in “lockout.” This may prevent your line from consuming resources that might result in denials of service to other customers.

Keep in mind that the problem may not be in the phone itself – instead, it may be a problem in the telephone jack or the wiring. If moisture gets into ANY phone jack anywhere in the home, it can cause the connections to corrode and eventually to short out, which could cause some or all phones to stop working. Bad splices, particularly if exposed to moisture, can also cause a phone to stop working.

If you suspect a phone of being bad, try it at a friend or neighbor’s home where you know the phones are working. Also, if possible, try swapping the line and handset cords with known good cords from another working phone. The vast majority of phone problems can be traced to bad cords and/or bad or corroded modular plugs.

If a phone stops working after a thunderstorm, it’s possible that lightning hit the phone line and caused a voltage surge that damaged the phone. The actual hit could have occurred several miles away, and traveled down the line to your phone.

If a phone won’t dial out, make sure that there isn’t a tone/pulse switch set in an incorrect position (such as midway between the two positions). Note that pulse dialing won’t work if you are using some VoIP services, and tone dialing won’t work on some telephone lines.

If a phone won’t ring, check to make sure the ringer volume or on/off switch isn’t at the lowest or “off” setting. Also, some very old phones may have frequency-tuned “harmonic” ringers intended for use on a party line, and won’t work properly on today’s private phone lines due to a difference in ringing frequency.


Working on telephone wiring during a lightning storm can be fatal. Telephone wires go outside. Whether above ground or underground, they still are all vulnerable to lightning. The telephone company adds lightning protection devices outside, but the primary purpose of these devices is to protect their network from indirect lightning strikes (where lightning strikes near but does not actually hit the lines. A direct hit can start fires, turn your telephone or outlet black, and possibly kill you if you are holding the phone or working on the wires. If you need to be speaking on the telephone during a lightning storm, you should use a cordless phone or a speakerphone — hardwired phones can bring the lightning from outside all the way to your ear. An industry slang term for ringing voltage is “jingle juice.” You will only need to touch the wires or internal parts of a ringing telephone once in order to understand this. You can receive a very annoying, though usually not fatal, shock while working on telephone wiring, especially if the phone rings or is dialed (in the case of a rotary dial/pulse phone) while you are touching the wires. The shock will be exacerbated if you are standing on an uninsulated or wet surface, if you are touching both wires at the same time, or if any other part of your body happens to be touching a grounded metal object.

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