Can a phone extension socket cause buzzing on a landline?

[paralucent]

I have been helping my brother set up his new 21CV internet phone line. His router is in an upstairs bedroom. When a phone is connected directly to the router the sound is fine, but when the router is connected to an extension socket there is a buzzing sound/interference on the line. I have managed to identify the extension socket that is causing the problem but what I don't know is whether the socket itself is faulty or whether loose wiring could be to blame. There is very little slack on the wires to play around with and I don't want to rip out the wires multiple times in the hope of finding a solution.

Any ideas?

 

[Diver Fred]

Make sure the external wiring is disconnected. Pull the 2-price master socket front half off and see if that stops the noise. If you have buzzing in only one socket out of a number check the colours are consistent across all sockets.

 

[opps]

You could buy a roll of solid core telephone cable and run it upstairs from the master socket. Then connect it to a socket plate and see if that works OK.

BTW, only two points on the plate should be in use- 2 and 5. The number 3 was for the bell ringer in old skool phones, it often created cross noise.

50m of cable will cost less than £11

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If it works OK, you know that there is an issue with the existing extension wiring.

 

[sparkymarka]

Is that extension filtered from the broadband ?

 

[paralucent]

No; it's a cable modem.

This problem is likely to repeated for a lot of people during digital switchover. The 'digital' phone line master socket (the router) is often nowhere near the old analogue master socket. The router is then connected to a defunct extension socket, and hitherto unknown problems with the internal wiring are revealed.

 

[paralucent]

I found the culprit! A faulty adapter was to blame. The sockets and wiring were fine.

There are two extension sockets in the upstairs bedroom. Normally these would be hard wired, but one of them ended in a RJ11 plug. The RJ11 plug was connected to an adapter, and that adapter was plugged into the phone socket. The adapter was faulty, hence the interference/buzzing. It had been disconnected while the analogue line was active (DECT phone connected downstairs), and it was only when it was reconnected for the new digital line upstairs that the sound problems materialized.