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Are these line stats any good?


Are these line stats any good?

Can someone analyse these line stats and tell me if they sound right.

According to BT's web site, my line should be able to support a 3Mbps or greater ADSL connection via ADSL Max. But the reality is that I've only ever seen download speeds of 1.5Mbps on Max. I know that actual line conditions can make a difference but is it normal for the BT web site to over-estimate by this much.

Here are my line stats:

noise margin downstream: 8 db
output power upstream: 11 db
attenuation downstream: 56 db

noise margin upstream: 13 db
output power downstream: 16 db
attenuation upstream: 31 db

Router is ZyXel Prestige 660HW-61

I've monitored the noise margin downstream over the last few days and it varies between 6 and 10db. Attenuation has varied between 55 and 57db and router has synced between 1940 and 2340 recently. I've tried plugging my router into the test socket behind the master socket but that made no difference to the line stats.

I live 1.85km from the exchange as the crow flies (according to DSL Zone UK's web site), and prior to MaxDSL the most I could ever get was a 1Mb ADSL service.

Based on all that information do my download speeds seem about right or should I be getting more?

Posts: 275
Registered: 29-08-2007

Are these line stats any good?


With the stats you have quoted the speeds are about right. The important figures are downstream attenuation and downstream Noise Margin.
Prior to ADSL Max, the limiting factor was attenuation - >60dB possibly 512kb, 45 to 60dB gave 1Mb, <45dB gave 2Mb.
With ADSL Max, the system will try to sync at the highest stable speed. It does this by monitoring the Noise Margin (or SNR). The lowest figure for acceptable use is about 6dB. If the connection keeps dropping then it will sync at a lower speed to try and gain stability.
So your attenuation of 55 to 57dB would have given a 1Mb connection prior to ADSL Max, and the resultant SNR of 6 to 10dB is the best that ADSL Max can give you.
A 2Mb connection syncs at 2272 so it seems that you have got an improvement because of ADSL Max Cheesy
Your perceived download speeds of 1.5Mb could be due to conditions at the time and overheads (My 2Mb connection gives 1.85Mb with PlusNet Speed Test).

Hope that helps.
Posts: 16,787
Thanks: 1,920
Fixes: 132
Registered: 06-04-2007

Are these line stats any good?

I am still wondering why, with att of 2db and SNR of 13 I never see speeds over 6200 which is the fastest I have noticed as reported by both and PN Speedtest. This has only happned twice for each speedtester

With the exchange just a stone's throw away I am surprised I never see regular speeds greater than 4.9 to 5.3.

I know the line could be routed a longer distance, but with such good att & SNR surely I could get better speeds. I have a new filter direct to the master socket.

From day one of Max I have always synced at 8128.

Forum Moderator and Customer
Courage is resistance to fear, mastery of fear, not absence of fear - Mark Twain
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Re: Are these line stats any good?

and router has synced between 1940 and 2340 recently

Pity it hasnt been syncing at at least 2272kb - But it needs to consistently sync at or above that rate for 3 days to qualify for the 2 meg data rate. As it has been syncing lower than this then that probably explains why you've been getting 1.5 meg throughput.

Are these line stats any good?

Thanks for the replies. My router is syncing at 2496 this morning so let's hope it stays that way Cool

My stable rate is still stuck at 1000 but hopefully that should shift upwards over the next few days.