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SNR Attenuation Interleaving & Trellis


SNR Attenuation Interleaving & Trellis

Hi guys,

firstly I seem to have a stable, if slow connection back after a month of pulling my hair out.

I upgraded to business, and just before that I believe I had the maxDSL upgrade. I had continuous drops for the last month and about 5-20K download speeds.

So for others info - my dropped conn problems seem to have been solved by the following:

1) Installing a professional quality ADSL filter box in place of my 4/5 year old plugin adaptor.
2) Upgrading my old router to a Netgear DG384N

These two together have enabled me to connect @ 3800+ speeds where before I was at 1600-1800 with conn drops

3) Having interleaving turned on.

I know this is supposed to ruin my ping, but loaded up counter strike and it was reporting 30-40 as my latency and it seemed to play fine.

4) Moving my ADSL router and main filter box away from my computer equipment and right next to the BT master socket in the hall gained me a whole 1db SNR.

This may not sound like a lot but... to the question:

I am currently getting the following stats from the router:

Connection Speed Down: 3424kbps
Line Attenuation Down: 60.0db
Noise Margin Down: 3.9db (!!)

Connection Speed Up: 832kbps
Line Attenuation Up: 31.5db
Noise Margin Up: 7.0db

In the AM I get 6.2db SNR on the downstream but with the same attenuation.

Question 1: On speed tests I only see about 400kbps downstream - so why is it saying 3424kbps?

Question 2: Why is there such a gap in the upstream and downstrem Line Attenuation and SNR figures? Does this point to a fault on my line or is it normal?

Any info appreciated Smiley
Community Veteran
Posts: 1,229
Thanks: 1
Registered: 12-04-2007

SNR Attenuation Interleaving & Trellis


Re Q1 What is the info on this page saying your line speed should be? Click

Re Q2 It is normal for there to be the differances you are seeing.

What results do you get from the BT seed test? How to link

SNR Attenuation Interleaving & Trellis

Cheers for the reply - results are:

1) 500kbps - used to say 1500kbps....
2) 478 kilo bits per second

Does the reconnect every three days thing reset this to a higher value (as I seem to have a better conn now)?
Community Veteran
Posts: 1,229
Thanks: 1
Registered: 12-04-2007

SNR Attenuation Interleaving & Trellis


I should have said before that your snr is on the low side. That said, there are many here who have such low readings without ill effect.
Allthough I am surprised it is so low, seeing as you say you have interleaving allready enabled!

I don't know if reconnecting every three days is required or not, but it does suggest that on the pn "stable rate" link I gave you, so I guess it is the thing to do. I am on an usb modem atm, so I reconnect every day that I boot the pc.

From the looks of it the "BT speed test" and the "pn stable rate" page concur.

While you are getting such low speeds on the BT test there is no way that pn can give you anything faster.

Considering you say that your router synchs at 3424kbps >3800kbps, but you only get <500kbps from the BT test, it would appear that there maybe a problem with your exchange or line. [not sure].

I don't know what the lowest acceptable speed is on your business package before it can be raised as a fault to BT. You would have to relay the info you have acquired today to pn, either via the ticket [question] system, or maybe you could "pm" one of the nice COMMMS team here on the forum.

Maybe it just needs a few more days to sort itself out.

Either way I hope you have luck on your side! Wink