Keep a sure tested cord phone when testing the telephone wiring. This eliminates the possibility that the phone device might be the thing malfunctioning. Another way of making sure it's not the phone device at issue, connect it with a friend's live phone line, call it, and see if it rings. If it does or if it has a dial tone, the phone device is okay for telephone wiring testing. A simpler way is to gently tap the wire connection to the phone device and listen on the receiver for any static interruptions. If the static is there, it's a telephone wiring problem.

The telephone company has a phone jack or a small plastic junction box somewhere in the area where the phone is located. At least one outlet from the jack is available for the phone. To check the telephone wiring connected to or from the jack box, plug a phone with a phone wire into this outlet and check for dial tone on the receiver. If there's none, then the telephone wiring has a problem.

This becomes complicated when there are several phone jacks available. Check each of the jack boxes and each outlet in them. Use a working phone and its line. If other jacks are working while the rest are not, it's probably the NID or the telephone wiring connecting from it to the jack boxes. In such case, it's time to ring the telephone company for technical help. It's very likely that several of the jack boxes need replacement.

The NID compartment indicates which phone lines are connected to what jack box. If not, then checking the telephone wiring will have to be done the hard way—checking the phone lines one by one to see what line goes to what jack box. When this is necessary, make sure to mark what goes where as the lines are being indentified. The next time testing the telephone wiring is done, it would be easy to check. When checking the telephone wiring through the NID disconnect all lines from the inside and then connect the corded phone used for testing. If there's a dial tone, then the culprit is the telephone wiring going into the house. If there's no dial tone, call the telephone company for repairs.

Telephone wiring is made simpler by the use of colored wirings. Check if the colors of the wires match the colors of the outlets in the jack box. Or, check the telephone manual for the color coding of the wires used. Sometimes there are 3 to 4 colors used on wires to differentiate the connections of the telephone wiring system. With this aid it should be easy testing and locating phone line connections.