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[roseway]

This is a problem which my line suffers from intermittently. The phone goes crackly, but if I turn the router off the crackles stop. It still happens if I connect to the test socket, and changing routers and filters makes no difference. I've had a few visits from BT phone engineers, and one visit from an ADSL engineer, and they all failed to find any fault. The last time I got charged £188 for the pleasure.

This is of course immensely frustrating, so I'm trying to gather more information before I take any more action. Can anyone suggest what sort of fault could cause these symptoms? Without the router effect I would have said that it's definitely an intermittent high resistance fault (and indeed it does seem to be affected by weather) but the router effect makes me think it's something in the exchange electronics.

Any suggestions gratefully received.

[sevenlayermuddle]

The last time I got charged £188 for the pleasure.

OUCH 

It's not often we get the chance to try and help one of the Gurus so, at risk of making a clown of myself, here's my ha'ppence worth...

I'm thinking that whilst the phone draws much more current than the router, the router does still draw a small current and hence put some extra load on the line.   So, have you tried to see whether simply plugging in an additional phone (or perhaps taking another handset off-hook), which would also put a small additional load on the line, has any comparable effect?  I'm not sure what that would prove mind you, but it might inspire a clue or two.

[roseway]

at risk of making a clown of myself

Don't worry about that. I'm as capable as anyone else of doing just that.

Your suggestion is a fair one, but yes, I have tried plugging and unplugging phones, and it makes no difference. Even with all the phones unplugged, Routerstats still shows the erratic variation in noise margin.

[pintosal]

When you say you swapped routers, did you swap the power supply also?

Some other thoughts:
- Are you plugged into an extension lead with surge suppressor?
- On the subject of a dodgy mains power socket, try plugging your kit into a totally different socket.
- Could the crackling be coming from your PC? Is the noise still there with the router (unconnected to any PCs) disconnected from all PCs?

[waltergmw]

Hi Eric,

I take it from your last post that you still "observe" the same crackling pattern via Routerstats whether you have no phones connected or at least one connected and / or on / off hook ? That surely does corroborate your idea that it's exchange equipment.

The only other cunning plan a certain ISP employs in similar situations is to ask for a Cease and Reprovide as shown in the following extract from a fault log:-

"Can we ask for the Cease and Reprovide please as the old fault has had a Flex of the VC and a Tiepair Mod order. The C&R will change the cables and the line card."

I'm afraid though that this is rather clutching at straws.

Kind regards,
Walter

[roseway]

When you say you swapped routers, did you swap the power supply also?

Yes, I have routers with different PS requirements, so I always swap the PS.

- Are you plugged into an extension lead with surge suppressor?

No, I use a filtered faceplate, and the problem remains when I use the test socket.

- On the subject of a dodgy mains power socket, try plugging your kit into a totally different socket.

It's a thought, and I'll try that the next time the problem occurs.

- Could the crackling be coming from your PC? Is the noise still there with the router (unconnected to any PCs) disconnected from all PCs?

That's one I hadn't thought of, and I'll check it next time.

Thanks for the suggestions.

[roseway]

The only other cunning plan a certain ISP employs in similar situations is to ask for a Cease and Reprovide as shown in the following extract from a fault log:-

"Can we ask for the Cease and Reprovide please as the old fault has had a Flex of the VC and a Tiepair Mod order. The C&R will change the cables and the line card."

I'm afraid though that this is rather clutching at straws.

I don't mind clutching at straws, so thanks for the suggestion.

[jeffbb]

Hi
quote from 7lm :or perhaps taking another handset off-hook)

quote from roseway:Your suggestion is a fair one, but yes, I have tried plugging and unplugging phones, and it makes no difference. Even with all the phones unplugged,

Did you try putting more load on the line when the crackling is NOT there (as when router switched off ) by lifting another phone off the hook?

Regards jeff

[roseway]

Thanks, I just tried it with three phones. No change.

[orainsear]

You mention it could be weather related.  Does this problem tend to surface when it is or has been raining?  If you are currently experiencing crackling, what's the weather like with you at the moment?

[sevenlayermuddle]

I've a long drive home, and found myself pondering this to pass the time.

I thought, if I was designing a DSLAM and somebody told me that use of DSL caused constant crackling on the phone, I'd take it seriously and redesign my DSLAM.

However, if somebody told me that a crackle occurred every time bit-swapping was taking place, I'd probably not worry about it as much.  So, is there any chance the crackle could be a side-effect of bit-swapping, in which case the underlying problem would be more conventional in nature (eg REIN)?  Just a thought.

[roseway]

You mention it could be weather related.  Does this problem tend to surface when it is or has been raining?  If you are currently experiencing crackling, what's the weather like with you at the moment?

The line is quiet at the moment, but when it goes crackly it seems usually to coincide with some sort of weather, but not always rain. For example, it went crackly during the heatwave a couple of weeks ago. On other occasions it's gone crackly during hard frost or heavy rain.

[roseway]

However, if somebody told me that a crackle occurred every time bit-swapping was taking place, I'd probably not worry about it as much.  So, is there any chance the crackle could be a side-effect of bit-swapping, in which case the underlying problem would be more conventional in nature (eg REIN)?  Just a thought.

It's an interesting thought. Certainly, when the line is crackly a lot of bitswapping takes place, but I've always assumed that the bitswapping results from the noise on the line. I monitor the noise margin using Routerstats, and the noise is random in nature, not the sort of thing I would expect from REIN.

[pintosal]

Weather related crackling suggests a 'dry' joint somewhere???

[coolsnakeman]

Are you underground cabling or overhead cabling?? If overhead cabling could be an imbalance on the pole (basically a wire touching your phone line causing interference) weather conditions of course can tend to make this worse. Or possibly it could be the drop wire (if you have one) that could be faulty. When the ADSL (SFI) engineer attended your premises did he tell you what he did and what he checked (yes they are meant to tell you) and did he run what is called an APTS test from your premises to check your stats as his diagnostics on SNR should suggest to him where the fault could possible lie. Cease and re-provide might fix this if a TP mod has not already been done but in my experience its on a rare occassion it does as you may aswell do a lift and shift cause its only the e-side cabling that is changed nothing after that. If your undergound cabling have you had any road works done recently (annoying work men digging up the road) could possible be an underground fault. The other suggestion has already been put in there and that would be the joints which are at the exchange and i think the cab aswell so you will need another SFI sent out for that. Think its back to your SP about this they should have some sort of escalations team to contact BT interventions for a repeat SFI and a collaboritve diagnostics review (basically the SP calls smart BT guys at there tech support helpdesk who are usually ex transmissions engineer or field engineers and has a good ole talk over your case).