Sync speed stuck at 576k - noise margin 28db

Hi, I'd been discussing my broadband woes over the last couple of weeks with my boss at work and he suggested I post here and see if anyone had any ideas... (also apologies if it's a bit long/sounds like a rant, I'm getting a bit frustrated as you can probably tell:)

A couple of weeks ago I noticed I was getting some very slow download speeds and double checked what speed I was connected at only to my connection had dropped to what appeared to be about half a meg speeds. Since then I've tried pretty much every trick in the book to try and diagnose or resolve it including multiple filters, routers etc, using the test socket and reconnecting a large number of times in an attempt to get back to more normal speeds for what should be adsl max.

Bearing in mind last time I looked (a while ago) I was seeing speeds of around 3-4M, and when I first joined PlusNet was on a fixed 2M, and had no problems until recently in nearly 3 years of membership. This problem appears to have happened recently although I can't be sure exactly when, but seems to be sometime in the last month or so - for the light browsing I was doing at the time the speed drop wasn't immediately noticable and I don't usually keep a close eye on my speed, it was only when I had a few days off work and started to use my connection a bit more that I noticed.

Anyhow I raised the issue with PlusNet and they passed it to BT Wholesale, who say they don't believe there is a fault but want to send an engineer and are asking me via plusnet to make an appointment - only problem is the only times they can arrange are exactly when I'm at work, at a time when we're very busy and I'm unlikely to be able to take half a day off just to wait for an engineer, when I'm not even convinced the problem is at my end.

The reason I say this is the noise margin seems very high to me - I was led to understand that under broadband max the connection should be attempting the highest possible sync speed that will keep the noise margin above the "target snr" - which according to plusnet is 6db for my line. So why therefore do I see on my router's config page the following:

ADSL Link Downstream Upstream
Connection Speed 576 kbps 288 kbps
Line Attenuation 34.0 db 18.5 db
Noise Margin 28.7 db 15.0 db

Playing around with a program called RouterStats Lite I see that it pretty much constantly maintains all of these figures - particularly the noise margin which has on occasion dropped to 24db for a fraction of a second in all of about 2 weeks. At the same time the sync speed is *always* *exactly* 576k, being *exactly* the figure to give me an IP Profile of 500. One would expect if I was really having line trouble that it would vary at least a little bit- maybe go down rather than up, but to always stay on the exact same figure seems bizarre. I also seem to have a rock solid connection, the only times it seems to have dropped is when I am deliberately resetting it to try and see if I can get it to work- I'm not sure if that's necessarily a good idea but I can't think of anything else to try!

So is the solution to go with PlusNet and accept an engineer visit, in which case it'll likely have to wait until I can arrange to be in (probably sometime around February!!) or is as I suspect the case something up at the other end, such as BTWholesale suddenly deciding that I'm on a 0.5meg fixed rate connect despite having been on adsl max for over a year and a half?

You need to get a bit strong with Plusnet because those figures indicate with 99% certainty that you are now on a fixed 512kbps service not ADSL Max. The up and down connection speeds are exactly correct for that, and for that to be a coincidence - particularly the upstream which is rarely anything other than 448kbps even on quite poor lines - is extremely unlikely.

If BT Wholesale look at your line and see it is 512 fixed then there won't appear to be a fault will there!! ?

The suggestion at this stage by anyone of a BT engineer visit, and the passing on to you of the suggestion, is just ludicrous if you have submitted those stats to Plusnet support. Particularly if I am right, as it would be no fault found, and you would get a bill for about £185. Which you should have been warned about by whoever told you.

If you haven't submitted the stats but have just said what you post above them it is perhaps understandable - except stats are the first thing anyone should have asked for and I would be surprised if Plusnet support cannot see the connection speeds anyway if not the other figures.

I suggest you PM Metronet_James with a link to your post and your username/phone number and ticket number if you have raised one. Just in case he doesn't see your post in the near future.

Hi RobertoS,

Thanks for the response- pretty much exactly what I wanted to hear because up until now I was pretty much going off my own guesswork / limited reading up on broadband largely as a result of this problem - I was starting to wonder if I was going insane!

One of the people at plusnet put a (marked '[internal]') comment on my ticket which was the only other thing that seemed to indicate to me that I might be thinking along the right lines (i've taken the number out in case it's some kind of id)::
"Asset shows as MAX Broad Band data: [strange number] BT IPStream Max (IPHMDM) but appears to be a fixed rate service. Raising for further checks"

but everything since then has basically consisted of them sending the fault to BT Wholesale, waiting for them to reply and then when they did they said they were "unable to locate any service faults" and copied and pasted (I assume) the standard text about engineer visits (twice, for some reason). I was also a bit concerned about the possible fee (which they list as £169.20) although they do state that it applies if my broadband/phone equipment or internal wiring is at fault - as I suspect it's not, but also isn't a line problem either, I don't know what would happen...

Anyway thank you for the clear and concise response, I'll PM metronet_james with this post and my ticket number etc. and hope he can get to the bottom of it. Incidentally included the stats in my initial ticket to plusnet, highlighted them, included a routerstats log showing they were consistent, and even suggested that I thought my speed was being artificially "capped" at 576k for some reason other than line quality - although I have to admit I may not have phrased it particularly well at the time, I would have thought it enough info to go on.

I was guessing the £185 as I think it used to be £188 and I was too lazy to recalculate for the VAT drop, but adding 15% to their figure doesn't give anywhere near so take it as they say.

However I think if you do a search for people being charged for home visits you will find the bill often gets sent even if there is nothing wrong with the users stuff, just no fault found is enough, and some IIRC have had bills when it was a BT problem that got fixed or even mysteriously disappeared.

Roberto - It's possible that BT have capped the service at that level on an instable line.

Mike - Would you mind PMing me your username so I can have a look into the situation and see if there is anything that I can do?

Mike - Scrap that, I see you already have

Me again

I've been on the blower to BT, to let them know that we do not wish to book an engineer appointment as it's extremely unlikely to be anything between the master socket and the exchange that's causing the problem. It's more likely to be a DSLAM profilewhich I've asked them to change.

The circuit is still a Max circuit, rather than actually being a half meg one, despite the sync rates being identical. It's just been profiled incorrectly, which is a bit bizarre given that the connection hasn't been noticeably intermittent.

I've put the ticket on hold for 24 hours (which was a good read ) and hopefully by then we should have some movement in the right direction.

At least it's getting sensible attention now you are on the case .

(Re the profiling, will that be the new-style fixed speed setup that replaces the old type?)

Edited by RobertoS (Wed 07-Jan-09 12:22:00)

Not as far as I'm aware. I've seen similar over the last couple of years or so.

Hi James - I see from the ticket that you've passed this to BT - thanks very much for your help so far. Hope you enjoyed the reading :-)

Also thanks again to RobertoS the quick respose and helpful advice.