How to Fix a Hum in a Phone Line

Disconnecting test jack inside phone interface box.

Disconnecting test jack inside phone interface box.

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, disconnecting the test jack, and plugging 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:



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18 Comments on “How to Fix a Hum in a Phone Line”

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  • Official Comment:

    Thomas Boni Says:
    August 13th, 2019 at 2:12 pm

    Glad to hear these tips helped, Rose. Please, pass them along! 🙂

  • Rose R. Says:
    August 12th, 2019 at 6:25 am

    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

  • Leo Says:
    November 7th, 2017 at 3:20 pm

    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?

  • cris Says:
    May 11th, 2017 at 7:06 pm

    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

  • Lee Says:
    March 28th, 2017 at 3:17 pm

    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.

  • Darla Says:
    December 8th, 2016 at 9:52 pm

    How does it work if you’re in an apartment building? Trying looking in box outside just not sure what I’m looking for.

  • Roland Says:
    January 27th, 2016 at 1:22 pm

    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

  • judy Says:
    February 14th, 2013 at 2:52 pm

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


  • J. Post Says:
    August 6th, 2011 at 2:09 pm

    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

  • Jessica Says:
    December 20th, 2010 at 2:41 pm

    Great guide! I had my hum fixed in no time. Thanks so much for posting.

  • George Says:
    September 29th, 2010 at 7:59 pm

    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?

  • D.Learn Says:
    September 26th, 2010 at 3:23 am

    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?

  • sheila Says:
    September 17th, 2009 at 5:13 pm

    Great website!! I love the visuals it is a huge help when doing the project.
    Thank you 🙂

  • Official Comment:

    Ben Erickson Says:
    September 14th, 2009 at 8:02 am

    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.

  • marym Says:
    September 13th, 2009 at 9:40 pm

    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.

  • Richard Houser Says:
    May 14th, 2009 at 2:48 am

    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?

  • Tom Willow Says:
    April 29th, 2009 at 11:40 am

    If the hum is coming from the power lines above the phone
    lines, have the power company disconnect the power lines.

  • diane Says:
    December 28th, 2008 at 6:57 pm

    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

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How to Fix a Hum in a Phone Line