How to Check Phone Lines for Problems

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Diagnose Phone Problems

When your phone line is not working well, it can be frustrating to try to determine the source of the problem. Phone line equipment can become damaged over time or a lightning storm can cause phone line problems. Whether your phone line has static, no dial tone or volume problems, you can check your phone line to help determine the source of the problem.


Step 1

Check your connection. Make sure your phone is connected to the phone line. If you connect your phone through another device such as a modem or answering machine, disconnect the extra device and plug your phone directly into the phone jack. If your phone line works correctly without the extra device, your phone line is working properly. Also check the ringer volume on your phone to make sure the volume is not turned off.


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Step 2

Change phones. Plug a corded phone into the phone line where you are experiencing problems. If the problem is resolved, the problem might be your phone, not the line; if it's a portable phone, it could have a signal problem. Make sure to change phone cords along with the phone to rule out problems with a phone cord.


Step 3

Disconnect all extra phone equipment that plugs into your phone line, including modems, fax machines and additional phones. Leave only one corded phone plugged into your phone line. If the problem still occurs, plug your phone into every phone jack in your home to verify the problem is throughout your home and not isolated to one outlet. If your problem was resolved by unplugging devices, attach each device, one by one, to see if the problem returns. If it returns when you plug in one device, you know your problem is with the device.


Step 4

Call from an outside line. You can call from a cell phone or another land-based phone line. If the problem still exists, the problem may reside in the phone lines outside your home.

Step 5

If steps 1 through 4 do not fix your phone line problem, call the phone company from an alternative phone line. Discuss the problem you are having with your phone line and all the steps you have taken to check the phone line for problems. Your phone company will probably call your phone line to run some diagnostic tests. Based on these tests, they can determine if the problem is inside or outside your home. If the problem is inside your home, you might need a professional to diagnose the problem using line-testing equipment. If the problem is in the line outside your home, the phone company is usually responsible for fixing the problem.

Things You'll Need

  • Corded phone

  • Phone cord

  • Cell phone


If you recently had a DSL line or Home Security System installed, check with your service provider to make sure you have the necessary filters on your phone lines to prevent phone line problems.


Do not work on your phone line during a storm because lightning can enter the phone line and cause physical harm.

Do not work on your phone line around water or with wet hands.

Turn off devices such as modems before unplugging them from your phone line to prevent damage.