BT Quite Line Test / Bad Earth?

Hi all,

Brand new line, installed middle of last month. Couple of days ago the BT's DLM decided to change my target SNR from 6db to 9db, thus decreasing my sync speed by an entire 1Mbit. I've had A&A put it back to 6db for the moment, but it may flip again.

A&A support have said it is due to the modem clocking errors on the line. I had a look at my modem stats and the FEC count is always increasing fairly uniformly - 12,253 FEC errors in half an hour. This doesn't seem to affect line throughput or stability.

I've swapped filters around etc etc and there's no real improvement, so I finally decided to dial 17070 option 2 to do a quiet line test. I did this and clocked a noticeable mains 50Hz hum on the line. Same result whilst having the phone directly plugged into the master socket.

But there is more. The master socket is in a small storage cupboard, so I've placed all my internet and broadband related hardware in this cupboard so its out of site. I've also put my NAS in there. There are couple of devices I know that are not earthed. The NAS is one of them, and I suspect the 3com wireless access point/router might be too. Why do I suspect this? If I perform the quite line test, and touch the casing of the NAS unit (which even has black paint on it) or the underside of the 3com unit (which is just bare metal), I get a really noticeable amplification in mains hum - not just a bit, fairly substantial! Is this normal?!

I don't have another phone to try the quiet line test with. I guess it could be the phone (it's a very cheap one), but if its not the phone, could there be something wrong with the line install that warrants opening this issue as a line fault?

Thanks.

Just a thought, did you use the test socket inside the master for the second quiet line test, or just the normal external socket? If there are any extensions connected to this line you need to use the test socket for the test, to eliminate any noise picked up by the extension wiring.

I hadn't done this, but I have now.

Same result.

There are only two extension points in the flat. One in the kitchen (which I don't use, has nothing attached, not even a filter) and the other in my room which only has a phone attached (with filter).

What do you reckon?

Having the master sat amidst the computer kit is asking for trouble.

What you need to do is experiment with turning off kit and determining which if any are affecting the number of FEC.

FEC errors are errors that have been caught and corrected by the interleaving.

likely to be unbalanced circuit making it hum. Disconnect extension wiring and try again.

I appreciate your comment. There's been no improvement of the line since I opened this thread. But with interleaving on, it holds a stable sync, with minimal (nearly 0) errored seconds. So I'll just put this down to yet another poor(er) quality line, supplied by BT OpenReach.

As I plan to move to FTTC when it arrives, the master socket ain't moving anywhere. So all the kit I've put next to it will stay precisely where it is. At least on FTTC, it will be a shorter line running VDSL, so less prone to line noise. That's the one thing that's always grated me about ADSL and long lines - more potential for things to go wrong with the signal on the wire, issues which, sometimes, just can't be resolved - or maybe they can, but diagnosing what's causing them is nearly impossible, and extremely time consuming.

Like ADSL is to dialup, VDSL/Fibre/Cable is to ADSL. In my eyes, it will always be a technological fudge to provide broadband to most of the population of the UK, in the cheapest possible way. I'll give BT credit for that; they've done a pretty good job of it. If I had my way though, I would go cable/fibre every time, but no joy in this new build I've just moved into.

In reply to a post by mixt:

I appreciate your comment. There's been no improvement of the line since I opened this thread. But with interleaving on, it holds a stable sync, with minimal (nearly 0) errored seconds. So I'll just put this down to yet another poor(er) quality line, supplied by BT OpenReach.

Hi mixt, I'm curious, did you follow the advice from the randomjointer and mr saffron to fix your line or was it something else?

Is your test phone corded or cordless, the reason I ask is that the power supplies from some (mainly cheaper) cordless phones are electrically very noisey.

Mains hum is very rarely caused by the Openreach side of the line, regardless of installation qaulity, but like rj says extensions using unbalance cables (non-twisted alarm wiring) can be culprits.

Also severe earth contact faults on the line (Openrach side) can sound very much like mains hum, so if you were to report it, this would be discovered when they run a remote line test.

Good luck fault finding, it sounds like a tricky one

>>Also severe earth contact faults on the line (Openrach side) can sound very much like mains hum, so if you were to report it, this would be discovered when they run a remote line test.

Severe earth contact faults would also cause bell problems. Ring Trip, Continuous ring etc. Far more likely to be unbalanced internal wiring IMHO.

Like, I suspect, both RJ & PM I would really like to know the result of:

(1) tuning off and isolating all mains-powered electronics in the cupboard
(2) connecting a basic wired telephone to the NTE5A test socket
(3) performing a quiet line test

If mains hum is still noticeable, it really should be reported as a voice line fault -- without any mention of broadband.

Edited by burakkucat (Fri 22-Apr-11 22:28:13)

In reply to a post by RandomJointer:

>>Also severe earth contact faults on the line (Openrach side) can sound very much like mains hum, so if you were to report it, this would be discovered when they run a remote line test.

Severe earth contact faults would also cause bell problems. Ring Trip, Continuous ring etc. Far more likely to be unbalanced internal wiring IMHO.

Yeah agreed, good point. Maybe 1 leg contact, earth leg to earth? They don't always ring trip, it's those ******* rectified loops that generally come with earths on both legs that are killers for ring trip.

Either way if mixt is unhappy then it's definately worthwhile doing some basic checks with a known good corded phone in the test socket, before reporting it faulty.

In reply to a post by burakkucat:

(1) tuning off and isolating all mains-powered electronics in the cupboard
(2) connecting a basic wired telephone to the NTE5A test socket
(3) performing a quiet line test

Done this morning. I even unplugged the 6 way from the wall. Plugged phone directly into master socket, with the front panel OFF (internal wiring removed from the equation) and the mains hum persists. There is occasionally a faint flutter of crackle on the quite line test too - I guess this will be causing the FEC errors that the modem is clocking all the time.

I think it's maybe time to open a fault case, a voice line fault as you suggest. I will have to go through A&A for this however, as the line managed under my account with them.

In reply to a post by mixt:

Done this morning. I even unplugged the 6 way from the wall. Plugged phone directly into master socket, with the front panel OFF (internal wiring removed from the equation) and the mains hum persists. There is occasionally a faint flutter of crackle on the quite line test too - I guess this will be causing the FEC errors that the modem is clocking all the time.

I think it's maybe time to open a fault case, a voice line fault as you suggest. I will have to go through A&A for this however, as the line managed under my account with them.

Right. So you've traced the origin of your poor broadband connection to the quality of the line / joints / etc at the OR side of your NTE5A.

Let A&A know of your voice line issues and they will quickly get OR on the job to resolve the problem. When the OR engineer arrives, just talk about the mains hum being detectable during a quiet line test via the NTE5A test socket.

Well this is just so convenient!

I opened a support ticket with A&A at the start of this week, and after speaking with A&A support, they arranged for a BT OpenReach engineer visit on Thursday next week (5th May).

I thought I would do some modem/line checks again this evening, purely out of curiosity. And I'm glad I did. ADSL is now syncing a whole 1 Mbit faster than it ever did before. I pick up the phone and there is now no mains hum, at all. In fact, it's probably the quietest line I've ever had the pleasure of listening to. No interference when touching the casing of any nearby unearthed appliances.

So in classic predictable BT style, someone has fixed the problem, they haven't told me they have fixed it, they haven't informed me or A&A that they were going to do this, so had I not done this check this evening, I would have been made to look like a complete idiot when the engineer shows up, plugs in his equipment and says to me 'what line fault? I can't hear anything' - at which point, they would also charge me 70 pounds for the privilege of the call out.

BT seriously [censored] me off. They pull this stunt ALL the time, even at an ISP I used to work at years ago back up north. Raise fault, fix it 10 minutes later, and bounce the fault back going 'what fault?'. Ass holes.

Now I have to request A&A to cancel the BT OpenReach engineer visit scheduled for Thursday, and lets hope they can, because if they can't, someone is going to be paying £70, and that sure isn't going to be me.

I wouldn't take it too personally dude.

If someone else in the area has had a similar problem and reported it (before you). An engineer may have investigated their fault, found (for example) a wet joint, which is common to your line and another 10, 20, 50, how ever many other lines. When the joint is dried and remade then your line, as well as the others, will be fixed also. Just a thought.

Did your SP tell you the results of the line test they ran?

The fact remains that even back in the days before aggressive charging was introduced, an amazing number of "no fault found" instances occurred, but the long-standing fault disappeared.

As it can now lead, as the poster pointed out, to a questionable charge, it is no longer a laughing matter.

If I were in your situation, I would advise my SP exactly what has happened and suggest that they should now cancel the OR engineering visit. As you are with A&A, and they are reputed to be "top class", there should be no problem.

In reply to a post by RobertoS:

The fact remains that even back in the days before aggressive charging was introduced, an amazing number of "no fault found" instances occurred, but the long-standing fault disappeared.

As it can now lead, as the poster pointed out, to a questionable charge, it is no longer a laughing matter.

"Aggressive charging" is bad enough, but manufacturing faults on a line (as I'm assuming is what is being implied here) so the company can benefit for a fault not found charge...

That is very serious, but I would suggest if you truly believe that to be the case, you do the responsible thing and report your suspicions to OFCOM instead of a forum?

You misread me polemonkey .

I didn't (mean to) imply faults have ever been "manufactured".

Just that even before broadband existed faults have been known to disappear once investigated.

This is common in all computer installations, never mind telecomms. No doubt in many other spheres of activity as well. The mere attachment of test equipment or running of diagnostic software can clear problems, especially if the disconnection of something else is involved.

In the past it was merely worthy of a wry chuckle. Now that it may lead to charges it is a concern.

Perhaps you could guarantee that if the OP takes no action that his now disappeared fault will not incur a charge for the engineer's visit should it take place?

Bearing in mind that BT systems seem not to pass on one engineer's report to the next investigating the same fault, the chances of the correction of a fault which possibly affected several lines being cured due to investigating one case thereby causing all other open similar faults in the area to be checked for continued relevance seem to be remote.

Oh right THAT'S what you meant! Sorry to misquote you (put words in your mouth!), my paranoid mind working overtime

In reply to a post by RobertoS:

Perhaps you could guarantee that if the OP takes no action that his now disappeared fault will not incur a charge for the engineer's visit should it take place?

No, mixt's absolutely right to cancel. It's too risky letting an engineer come round because obviously the engineer won't find a fault (because it's now disappeared) and so his notes will reflect that no fault was found, potentially leading Openreach to charge the SP and then the SP may pass that charge onto mixt!

In reply to a post by RobertoS:

Bearing in mind that BT systems seem not to pass on one engineer's report to the next investigating the same fault, the chances of the correction of a fault which possibly affected several lines being cured due to investigating one case thereby causing all other open similar faults in the area to be checked for continued relevance seem to be remote.

Kind of. Fault notes on the SAME fault do (should and normally do) get carried over to any further faults off the same directory number or fault reference. BUT multiple faults off, say, a common cable, joint or pole, don't often get linked together because the process would require too much investigative work on behalf of the fault help desk (or whoever issues faults to engineers). This is a shame because if the systems worked like this it would lead to better customer service, but that's another story...

In reply to a post by polemonkey:

This is a shame because if the systems worked like this it would lead to better customer service, but that's another story...

If internal systems are such that customers can be unnecessarily charged substantial amounts, it's more than a shame, the words "incompetency" and "lack of forethought" come to mind.

Oh, hang on, it's BT...