line stats, speeds, profiles, modulation

What's up with my sync speeds?

Line Attenuation: 39db
SNR Margin: 6db
sync speed: 5985 kbps

Various theoretical speed calculators suggest that I should get over 9000 kbps on ADSL2+.

My questions
1) Do PLUSNET have their own profiling/capping system? And does it require manual intervention to increase/raise/remove it?
2) Can a DLM negotiate modulation down (ie to ADSL2) to improve stability? And if so would it ever revert back automatically? (see below)
3) Do I just have to accept these speeds or is there some magic word I can use to get closer to the theoretical limit?
4) Is it worth trying to manually force my SNR Margin down a bit? I've seen it blip down to 4 briefly - though I don't monitor it.
5) Can PLUSNET see the modulation type for the current data link? When I raised a ticket yesterday explaining my problem and asking to be put on ADSL2+ the response I got was that I was already on ADSL2+ "Current Provisioned Product = WBC MAX24 mb/s (ADSL2+ Annex A) 448kbit/s Upstream.".
To me this just says the line is capable of ADSL2+ not that my session at the time was actually ADSL2+. But, I'm not in the business so maybe it says more than that.
6) Are the number of likely responses to new posts inversely proportional to the length of the post?
7) Is anybody still reading this?

FYI - I'm not unhappy with what I have but I'm happy to have more if it's possible.

What I've done
Yesterday I checked my router and found that it seemed to be reporting to have a trained modulation of only ADSL2. Today I think I have forced the router into ADSL2+ and reset the router. It now seems to be ADSL2+. No change to line stats or sync speed.

In the past week I have had a few link/PPP resets whilst getting interleaving turned off. But this sync speed has not dropped much... I'm currently speed testing at 500kbps slower than my best results which does not seem significant.

It's a newish contract (6 months) to an older house (12 years) but no new wires I don't think (though a BT visit was required for initial connection). It was a bit flakey at first.
A few months ago there was a physical line fault (where phone was off and broadband was even slower) that BT repaired (disconnected/broken wire or something I think).

Apart from the above the line very rarely loses sync. I can't recall a loss of sync since the repair was sorted.
PPP/Link Prortocol (or whatever... the connection to plusnet) is a little less reliable but still stable for weeks at a time (I notice the dropped link because I have to bring it back up manually for some reason - but I just restart the PPP).

Sorry for the length of post and any misuse of terms (I'm still learnin!)... tried to give enough info to get some good pointers on how to squeeze more out of my connection!

Thanks for reading.

Keeping to the numbers

0. Need to see upstream figures to get the full picture
1. PlusNet do not have anything to cap connection speeds, only the BT Wholesale system, and that may apply banding if it thinks the line is unstable but connecting at similar speeds all the time.
2. Yes it can, but if you can change it with your modem then DLM is not doing that
3. Magic word, is can you reset DLM as it may be banding has been applied to the line.
4. If you want, but generally delays any improvement from the automatic system
5. They can see line history data. The 448 Kbps upstream is an oddity you can ask for that to be unlocked and will probably double.
6. Yes
7. Yes

Generally takes two weeks of stability for DLM to start handing speed back to you.

Read about the ring/bell wire and check/remove it at the master socket.

Thanks.

I didn't realise upstream helped:
attn: 11db
SNRm: 6db
sync: 963kbps

Do you think my downstream speeds should be better?

I remember now that I already got my upstream doubled after the line fault saga having read about it here - thanks!

But, you can see why I put little faith in the response from plusnet... I was clearly getting quoted the standard line provision for my exchange and my connection had not been checked for modulation at all. Maybe I used the wrong word... modulation?

That is what I meant by "magic word"... it seems you can get very different responses just by using the right keyword/buzzword.
I know I'm on a wholesale package but should I really have to support it myself too!! haha!

In the absence of any suggestions/advice I'll leave it alone for a few weeks with the forced ADSL2+ and see what happens to my speed.

Thanks again.

Thanks.

Will check the ring wire again but I'm pretty sure I checked it when I first moved in and there wasn't one... but thanks for the reminder... won't hurt to look again.

Upstream looks fine, but the the attenuation is oddly a lot lower than I would have expected based on the downstream figures.

No extension wiring involved, that may be a poor quality aluminium?

Downstream attenuation is usually double the value of the upstream (or there a bouts)

Hmmm, no extension but I'm not in the master socket anymore as there didn't seem to be any difference for the very short tests I did (but that was before the line fault).

When I next do a restart I will go back to the master/test socket and stay plugged in there for a while... bit inconvenient with it being in the loft, but worth a try.

Thanks for the help.