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Line noise, interleaving etc basic questions

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Line noise, interleaving etc basic questions

Hi,

Just wondered whether you know of a good website that explains the above? I'd like to know how to tell a short line from long one, normal snr levels etc. I have a vague idea but would like to know more.

We've had our share of problems moving to a house that's far from the exchange so would like to optimize our connection. Our connection was brill for 2 weeks, then started dropping every few seconds and was pretty much unusable. Plusnet turned interleaving on but it's still dropping - not so much though. Reading the posts I also found out we don't have the ideal router, Netgear DG834G v2. So I'm off to buy a better router(Speedtouch 585 v6, I've been told).

Anyway, any info on those figures or suggestions on what to do with the connection(I'm not moving for another 5 months so don't suggest it!) would be appreciated!
5 REPLIES
Community Veteran
Posts: 14,469
Registered: 30-07-2007

Line noise, interleaving etc basic questions

The usertools tutorial Understanding Line Loss and Measurements explains the basics.

The figures stated are pre-Max on the old 512/1M/2M fixed speed connections. The only difference is line attenuation is ignored and its SNR that determines the speed you get i.e. sync speed is increased until the SNR reduces to 6dB (for BT Max) or 12dB (for LLU).
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Line noise, interleaving etc basic questions

This site contains a fair bit of useful info, no nonsense, and failry full explanations.

http://www.kitz.co.uk/adsl/lowSNR.htm

browse through the rest of the pages for Line Attenuation and lots of other good explanations.

My DG834G (v1) has been fabulous for many years - I'm dubious of the negative press in some areas.

Recent personal experience says "check if your external phone line is rubbing on your roof tiles", also use the RouterStats program to monitor your noise throughout several days and look for a pattern - is your SNR steady all night then goes nuts when you get up (dodgy boiler maybe ?) or is it just bad all the time (maybe a higher SNR target would help stability).

2 weeks of good connection followed by problems suggests a fault or change somewhere - any new Sky boxes, cordless phones, new(er) neighbours, new power adapters (bricks) next to your phone line ?
Community Veteran
Posts: 14,469
Registered: 30-07-2007

Line noise, interleaving etc basic questions

zdenka,

I forgot to ask what firmware version you are running as the problem with disconnects when SNR 'appears' to reduce on that router was fixed in the 3.01.31 firmware release.
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Line noise, interleaving etc basic questions

Thanks for the info, will have a look at it in the morning.

To answer the questions ; nothing new on the line. Previous tenants actually struggled with this issue and basically after hassling BT and their isp Bt engineer came out and said there was a fault on the line and supposedly "fixed" it? It wasn't much better after that though and they learned to live with it. WE can't as my husband works from home and internet is essential. BT says the line is fine so is it worth hassling them about it?

Second question, firmware. Ahem, I only upgraded that this evening so really will have to see how the line behaves over the weekend.
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Line noise, interleaving etc basic questions

Thanks for the help, since the firmware upgrade the router hasn't bleeped! Also Skype is back to normal, since the interleaving was switched on it was very robotic!

The SNR info made a very interesting read, thanks for that! I am a graduate of the cisco academy and an MCP but things like that make me realize how much more there is to learn - that's why I'm starting uni in September!