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Modem causing noise on telephone landline

Posts: 1
Registered: ‎21-05-2021

Modem causing noise on telephone landline

Hi Everybody,

Mum's phone has loud crackling sound when the modem is plugged in.

Tried taking out extensions and changing filter but noise disappears when modem is switched off, then landline is clear for primary plus extension phones

She has single socket with double extender for two telephones.

anybody had this problem before or if Plusnet is watching can you supply another modem.



Bettys Son

Aspiring Champion
Posts: 2,317
Thanks: 296
Fixes: 28
Registered: ‎02-08-2007

Re: Modem causing noise on telephone landline

Best trying an alternative filter first.
Filter must be the "fist thing" in the socket, and the extension socket adaptor then placed in the filter's socket. Smiley
Plusnet Alumni (retired)
Plusnet Alumni (retired)
Posts: 2,319
Fixes: 113
Registered: ‎01-12-2020

Re: Modem causing noise on telephone landline

Hi there


I'm sorry to hear that you are having issues with your phone service.

Click play to watch a guide on how to resolve a few basic phone problems

The link is

<iframe width="560" height="315" src="//" frameborder="0" allowfullscreen></iframe>

If you are unable to watch the video for any reason the steps are outlined below.

We need to find your master socket, this is often the first telephone point where the line enters your home. If you’re still unsure of what that looks like, we have a guide here -

When you've found it you need to make sure it’s working properly:

* Locate your master telephone socket, and unplug all other equipment from the line (ideally, please try this from the test socket (behind the removable front plate of the master socket)
* Now take the corded handset and plug directly into the master socket.
* Pick up your handset and see if you’re still having the same problem.

If you have done all the above checks and the issue is still evident then we can arrange to send an engineer to you. Please note that if an engineer visits your premises and the fault is found to be caused by your internal wiring, your equipment the condition of Openreach equipment within your property and its boundary, or if no fault is found, you will be charged £65 to cover the cost of the engineer. This charge will also apply if you miss the appointment or cancel without giving us 2 working days’ notice. This is why we advise of the above checks.

If you wish to proceed with an engineer appointment we need the following information:

* Agreement that if the issue is caused by any of the above that you may receive a £65 charge.
* An alternative contact number preferably a mobile
* Availability should an engineer need to attend the premises, between the hours of 8am-1pm & 1pm-6pm Monday - Friday.


-Adam - Plusnet Leeds

 Plusnet Help Team - Leeds