How to Fix a Hum in a Phone Line

I have a loud hum in our telephone line. The phone company says it’s inside the house. Is there any type of a device that can locate the cause of the problem? – Jim

Hi Jim,
There are a number of things that can cause humming or static in a phone line including a short in the wires, a defective phone, interference from power wires or light fixtures, and a signal from another electrical device.

Here’s how to go about isolating and repairing the problem:

    • First, check to be sure the hum is coming from inside your home by opening the telephone interface box, which connects your home’s wiring to the telephone’s network. Then disconnect the test jack, and plug a corded phone into it. If you still hear the hum, then the problem is with the phone company. If it stops, the problem is inside your house.
    • If it’s inside, plug the house jack back into the interface box and unplug each phone in the house one by one while listening in on another extension. If the hum disappears, the problem is with the phone you unplugged.
    • If the hum persists, disconnect each set of wires one by one from the terminals in the interface box, and listen on an extension until the sound stops.
    • Once you’ve isolated the problem wires, check the connections at the jack, and try unplugging any electrical devices nearby that could cause interference.
    • If you’re still having problems, hook the other two color coded wires in the cable to the jack and interface box.
  • As a last resort, permanently unhook the defective wires at the interface box and run a new line from the interface box to the jack.

You can find out more about working on phone lines in the articles:



  1. I have the line with all these colored wires coming out which color goes were i know red to red and so on but what about the blue brown white on one side green on other where does the green go or the blue if the colores on the box are red black yellow and green but there’s orange on the wire

  2. I want to install a Digital Cordless Phone and the instructions say I need a RJ11C type modular telephone
    jack. Why can’t I just use the standard jack already
    installed in my home. Also can I get info on installing
    a RJ11C type from your website?

  3. We had a persistent hum in our phone. To the point where we were buying new phones to try and get rid of it. The phone company sent a guy and he said it was our problem, not the phone company. We put up with it for a while. Then, we had some DSL problem and the phone company sent a different guy out. He heard the hum. It wasn’t OUR problem after all. He followed the hum all the way to the phone company equipment one mile away from us. He fixed whatever it was and I thanked him profusely. My bad that I didn’t get his name and write to the company.

    • Hi Marym,
      Thanks for relaying your experience. I had a similar one a while back. Everytime it rained there was loud static on our phone line, but by the time the phone company would get by to check it out, the weather had cleared and the phone was fine. Finally, the arrrived in bad weather and traced it back to a bad connection on the pole a block away.

  4. Why would everthing that is plugged in the phone jack work but the phone?If I plug the phone and only the phone in the phone jack it works,but not if it’s plugged in the jack with the internet?Coulsd it be a damaged phone prong jack?

  5. The electric company just changed our meter. Now the phone has a loud hum. The electric meter is mounted above the telephone interface on the side of the house. Can this be causing the loud humming noise?

  6. As far as it goes for telephone color code.
    Line 1 is red/green or blue/white blue
    Line 2 is yellow/black or orange/white orange
    Line 3 is green/ white green
    Line 4 is brown/white brown

  7. I recently upgraded my wireless router for my computers but now have a terrible hum in my phone lines. How do I fix this?


  8. what kind of solder should be used to connect a telephone line to extend it to anew location. what kind of solder should not be used that would deteriorate the wire

  9. Great advice that helped me. I terminated all 4 wires , found issues in some terminals. However in the end the problem I had was that the telephone company wires were not terminated well in their box. I had coax telephone from time warner installed and the telephone line was still connected. Once I cut that the buzzing stopped.

  10. We have frontier, nee verizon, and yesterday all at once i got the HUMM! well. I started tracing everything back to the main box and that’s where it is. When I plug a phone directly in the jack I get the HUMM! I still have the usual crummy i-net but if the phone rings and then if I pick it up I can’t hear anythiong but that HUMM! (hm) So we know somebody that works for those people so we’ll call him and get an inside track on the customer satisfaction deal..whatever that is

  11. I’m having static sound on all my phones. The weird part is that started after I cleaned my air vent with a water hose. It’s that a coincidence or I actually did something to the line?

  12. To Danny Lipford,
    Thank you for sharing your knowledge. Previously, I’ve done various tests in trying to track down what’s causing the “humming” noise in our phone lines {Testing our NID box, etc}
    Then I came across your site which surpassed other sources I had previously researched. You provided more steps to test for, while listing several causes of interference I had never heard mentioned, along with detailed, easy to follow info and helpful instructions. Much appreciated

  13. This would be great if one knew what an telephone interface box was. Keep in mind some are newbies and explain such things in detail. Had to google all over the place to understand your instructions

    • Thanks for your feedback, A R! This is a more involved project than most of the ones we tackle.
      We’ve added some clarification. 🙂

  14. I’m in NZ.
    I have a phone with a cordless handset.
    When I press to get dial tone there is a fairly audible hum.

    When I place a call, the hum is there.
    When the other person answers and talks, the hum is there.
    But when I start talking, the hum stops, and when I start talking again, it stops.

    Any advice would be great thanks.

    Rob Wood


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