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Abnormal phone line noise, advice?

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Abnormal phone line noise, advice?

Just looking for advice on an odd problem that's come up recently.

I've been using Plusnet ADSL with a SAR110 router for over a year now with very little to complain about, sometime in January I added a switch and a second PC to my setup.

Sometime in the last month our phone line quality has dropped substantially, there's a strong background hiss now and sometimes crackle. The hiss is only present if my router is switched on.

I'm using a faceplate splitter and one unfiltered extension for the router, three filtered extensions. I've tried unplugging various phones or adding a plugin filter and it makes no difference. I know it must be DSL noise as if I switch the router on with the phone off the hook I can hear it negotiate.

Now I must add that things were working fine. At work we have a SAR110 switched on all the time, sharing the line with a fax, no line problems there as far as I know.

So what's changed and what can I do about it. Could something have been changed on our line, like BT working on the exchange?

If I ring BT I know the standard response is to tell us to plug a phone straight into the master socket, well I figure that's probably going to come up fine without the DSL service.
5 REPLIES
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Abnormal phone line noise, advice?

The facepalte filter can go faulty. After all they are only cheapo capacitor and resistor circuits. If the filter goes short circuit, it will put the DSL noise directly onto the phone.
Unfortunately, with a faceplate filter, you cannot simply substitute it for another.

There could also be a fault with the local BT wiring to the exchange, as has been noted by at least one other user with the same symptoms.
This sort of thing could have happened to your local BT green box.
http://portal.plus.net/central/forums/viewtopic.php?t=15961
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Abnormal phone line noise, advice?

Right now I'm figuring that as adding a plugin filter (I've got two of them handy) doesn't help I guess it's not the faceplate. It's a Solwise supplied faceplate not BT so I figure I can change the thing if it's really that, or try a master socket jerryrig sometime just to check.

I agree things can fail, I had a lightning damaged master socket once that made all the bells ring constantly.
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Abnormal phone line noise, advice?

If you have a face place filter, using in-line filters won't help since the line will have already been filtered.

Disconnect the router and check for noise on the line using a corded phone, if you still get crackles etc then you may have a faulty line. The only way to be sure is to test from master socket or even better the test socket (socket behind the main socket).

If you test from the test socket or using an unfiltered master socket, trying using in-line filters and see if that solves the problem. In addition try just connecting a corded phone direct and listen for noise.

If you get noise using a corded phone on an unfiltered line then chances are you have a line fault (which could be the local green box ).

(You must a corded phone for these tests, since cordless phones are subject to radio interference and cannot be trusted).
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Abnormal phone line noise, advice?

I don't have any cordless phones.

I just tried everything from the master socket, the only thing I don't have a substitute for is the 110.

I can definitely hear DSL activity. It's tolerable but it's there. I am not a bat, why can I hear it? :-)

I also hear a lot of crackling noise that seems unrelated to DSL, I guess I need to contact BT with a line fault.
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Abnormal phone line noise, advice?

Connect your phone direct to your master socket, i.e. no filter and no router.

If you still get noise, then chances are you have a line fault or faulty master socket. Raise a fault call with BT.

Your symptoms are exactly the same as I suffered just over a week ago and it turn out to be a wiring fault in the little green box up the road from my house. (well in fact a lorry had smashed into it :shock: )