I joined the trial in April 2009. After the initial training period my sync speed rose from 4250kbps and settled around 7600+kbps with a profile of 6500kbps. My SNR stayed on 6db down and between 5.5db & 6db up, pretty much the same as it had been for the last four years. There were a few days when sync speeds would fluctuate, but they usually settled back to 7000>7800kbps and my profile caught up a few days later.

In late June my sync speed dropped and my SNR rose to 15db, despite this being well chronicled in this forum very little feedback ever fully explained the cause of this widespread problem. After a long period of time my SNR dropped back to 6db and my sync rose to 7000+.

On 22/10/09 Plusnet proudly announced that ADSL2+ was going live, later it was then announced that more bandwidth was now available, it looks good on paper, but despite all the announcements and back slapping in Plusnet Towers my sync speed is now back to what it was before ADSL2+.

My SNR is now at 11.9db and rising, my sync speed is dropping yet again.

Like many other so called technological advances of today, only the successful parts of the exercise are factored into the final report. The troublesome issues are apparently discarded and hopefully forgotten over time.

At this moment in time my sync speed is 5583kbps with my SNR at 12.1 and line attenuation of 41.1db. my profile is 4000kbps.

I find nothing to celebrate here!

John B.

lenseman

My experiences almost exactly mirror yours.  I had a good initial response on ADSL2+, but this sharply fell back, to basically pre ADSL2+ levels. Now have an SNRM of 15dB, with a sync of 5024, on a line with 44dB attn (used to be 41 on ADSL1!!!!!).  Upstream has also appeared to have been capped at 440.  Not really a good advertisement, and I was amazed when ADSL2+ went live on PlusNet. In my view, and many others, it is crippled by a DLM, that is much to agressive.  My line pre adsL2+ was stable for months at 6dB, now it needs to be at 15dB.  The matters have just not been adressed. Also where was the feedback mechanism for this trial. Apart from forum posts, no formal feedback mechanism, and and results have ever been published.  Not very good really

Chris

Look out for 'banded profiles', the latest BTW evil to beset 21CN, AFAIK these don't exist on 20CN.

These nasty things suddenly drop your connection speed by around 50% and don't let go 'till they fell like you've been punished enough.

DLM could be a good thing but at present it is so 'one-sided': drop a connection a couple of times and you get limited speed for days / weeks, keep a perfect connection and you might speed up eventually.

This is NOT a Plus Net issue it's the BT infrastructure, but it's another way that can make 21CN slower than good old MAX DSL!

If you live in the same street as the exchange or 20 miles away then 21CN is almost definitely a good thing.  In between these extremes it is not so clear and the DLM does seem more aggressive and less forgiving.  With more frequencies to play with 21CN should always be capable of being at least as good as 20CN but this is not turning out to be the case for everybody.

I had a load of trouble.
Got my noise margin reset to 6dB a number of times via Plusnet.
Latest value was 7dB, so I used DMT to knock that back to about 4dB in the daytime.
Amazingly, that has been super-stable! 

I have suffered the effects of banding in the past and I have probably been banded again.

The ADSL2+ 21CN fiasco as proved to be a bigger comedy than Only Fools & Horses.

BBCi player are streaming HD but due to the over active DLM I am no longer able to view anything without first downloading the full program. So one improvement in technology is being screwed by another piece of technology. That sounds like modern day Britain!

I am in fear of re-booting my router in a vain attempt to increase my connection speed because my SNR usually rises again. At the moment I have been connected for more than 143 hours without a reduction in my SNR, it used to be 6db at the moment it is 10db+.

I believe that the high SNR is artificially created by either BT or Plusnet in an attempt to limit the end user. My connection is slowly deteriorating again, but when a fault is reported I am requested to jump through the hoops and play ticket tennis until all of a sudden someone somewhere flicks a switch and my SNR drops below 6db and normal service is resumed for a while.


It would have given Plusnet more credibility if they had waited until the problems on 21CN had been sorted before going live, but it seems they are in a contest to see how many customers they can lose in a given time!

My package is amusingly called Unlimited, how Plusnet can call such a heavily throttled product Unlimited amazes me, surely that is misrepresentation?

John B.

It is unlimited in the sense that you can use as much data as you want. In reality its so heavily throttled, you cant utilise it for anything, so it actually defeats the object.  Interestingly its been removed from sale, and replaced with a 21Cn variant called Premium I think. I think marketing got this one all wrong!!!
My SNR no matter how may reboots, or whatever is struck at around 15-16dB, but I get a sync of 5088, which is about what I got on 20CN, Also upload is stuck at 440, which is interesting slightly slower than MAXDsl.  Oh well, at least is quite stable now.......

I'm considering a move from BBYW3 to Premium (mainly for the 80GB).
As part of the 21CN trial, I'm already on it 21CN.

This is a 7.2Mbps sync, reduced by BT to a 6Mbps profile, reduced by protocol overhead to 5.5Mbps!!!!

It seems a bit sluggish - so no way am I changing anything for a while!

Jeremy,

With those sync speeds, you should eventually see a change in profile to 6500Kbps.

An account change would have no bearing on your profiles & connection speeds.

James - I think I've finally caught you out here
Sync rate = 7203kbps
But https://portal.plus.net/s...s/dslmax_guide.shtml#Sync says that I need to attain 7392kbps to get a 6500kbps profile.
I don't know if it's significant, but I used DMT to push my sync rate up to 7203kbps (and noise margin down to 4dB).

Guilty as charged!

I forgot to double check first.  Just made a foolish assumption

Thank you for correcting my schoolboy error