are there any checks i can do to my phone line/hardware as think i have a faulty line


Active Member

not sure whether this should have gone in isp or networking, please move if its in the wrong place.

i've recently been having problems with my bb connection with the downstream being reallu unstable, it goes up to max then down to zero in peaks and troughs.

overall its slowing down my dowload speeds plus its making gaming almost impossible.

i've run and on the dl part the needle is all over the place, but the upload is smooth as normal.

i've rang my isp (bt) and as usual the guy can barely talk english and doesn't have a clue what i'm on about and insists on going through all the usual stuff only to tell me my line is fine.

i've just had the house rewired and phone sockets put in every room, so i'm wondering could this have had anything to do with it?

are there any checks or progs i can run that will give me more of an idea what the prob could be??

thanks for your time



Distinguished Member
Did the problems start as soon as the rewiring was done?

You could try routerstats if you've got one of the supported routers:

That'll give you a graph of your sync speed and noise margin. It'll be interesting to see whether those stay fairly constant (3-4dbs variation for the noise margin in the short term, though more over the course of a day).


Active Member
to be honest i'm not sure:confused:

it was only when i tried downloading something with newsleecher that i saw the status graph was all over the place then started investigating.

i'm using a netgear 834g at the min, but i also have the bt homehub i got free, could be worth trying that?

will take a look at the link thanks alot:thumbsup:



Active Member
right i have that running but to be honest i'm not really sure what i'm looking for:rolleyes:

the noise margin is 11db am i looking for no more than a 3-4 db margin +/- 11db then?




Distinguished Member
As a first to test the line to see if this is causing the problems connect the router/modem to your houses master test socket (you will need to open up the plastic casing).

From the picture attacthed you will see the test socket is hidden to the left of the master socket.

If this provides the same problems then you know its the phone line itself, if it doesn't then its a problem with your in house wiring.


  • testsocket.jpg
    6.8 KB · Views: 40


Distinguished Member
the noise margin is 11db am i looking for no more than a 3-4 db margin +/- 11db then?

Noise margin is how much headroom there is on your connection. When it drops to 0 or below then your connection will be unsustainable due to noise and you have to reconnect at a lower speed. 11db is very good, my line never goes higher than 9db. When at 9db I get fluctuation between about 6-9db but if yours was fluctuating between say 3 and 14 rather than 10 and 12 then that could be indicating a problem.

As a first to test the line to see if this is causing the problems connect the router/modem to your houses master test socket (you will need to open up the plastic casing).

If you've got one of these then it's probably a good test to do, although I believe it disconnects the rest of your phone wiring when plugged in.


Active Member
got it sorted in the end it appears the new Av software i'm using scans every file i download so it slows everything right down.

disabled it now everythings working fine.

out of interest though my master socket is one of the old ones, with just the 2 wires coming in thats it.

thanks for the help guys



Standard Member

I had a similar problem to yours a while back and it sounds like the telephone line is damaged.

My problem was i was with sky broadband 8mb but the netgear router syncd at lower speeds all the time like just under 8 down to 6,4,2, eventually under 1mb which was not on. This happened everytime a phone call was made or received which reset the sync rate.

As suggested use the master socket to test the line with the front panel out so that disconnects the extentsions. If you still have the same problem then its a faulty line, though be aware if you complain to BT they do a automated line check and as long as voice quality is ok they pass it.

Mines was terrible with background hissing and scratches clearly audible but even after a BT engineer called he still insisted the line was ok. He finally traced the fault to a dodgy junction box in the bathroom which over the years corroded the connections (steam/shower). After this was fixed perfect 8mb sync rate and download speeds. Watch out as he tried to bill me for fixing it despite the line into the house to the master BT socket being their property and therefore their responsibilty to fix.

All i can say is BT customer support is really bad and the fault wouldnt have been spotted unless you politely insist on it being fully checked out.

A good program for measuring broadband speed is routerstats, just google it its easy to find!

Best of luck!


The latest video from AVForums

Podcast: Anthem AVM 70 Review, EQing Your Home Cinema Sound System and More...
Subscribe to our YouTube channel
Support AVForums with Patreon

Top Bottom