Thanks RobertoS,
I will leave it to its own devices now and just keep my fingers crossed.

Was this increase/change to ADSL2+ anything to do with me changind from fast to interleaved? and why did the homehub just restart on its own?

How will it get back down to ADSL2?

Sorry for all the questions

Edited by deleted (Wed 28-Mar-12 20:03:23)

In reply to a post by Greigster:

Was this increase/change to ADSL2+ anything to do with me changind from fast to interleaved?

I think you were still on ADSL2 after interleaving was turned on.

and why did the homehub just restart on its own?

Because that was when the DLM reset your sync-time margin from 6dB to 3dB. This causes a re-sync.

How will it get back down to ADSL2?

It won't without manual intervention, or loads of errors making the system change its mind. For now, be happy with ADSL2+ and the higher speed. Deliberately causing ADSL2 is geek-stuff and BT first line support wouldn't even know what you were on about.

On BT, with the Home Hub, I expect the idea is a dead duck anyway, without support setting it. Then if it wasn't the best idea in the world, getting it unset may be even harder. The only practicable way is with an alternative router of your own, where you can force it and revert it easily yourself.

Sorry for all the questions

I like trying to help.

Bob,

Would one see an increased downstream attenuation with adsl2 compared to adsl1 on the same line? If so would it still be less than adsl2+ ?

No ... N/A!

In reply to a post by RobertoS:

That has added considerably to your downstream connection speed.

Not much! And should be getting over 6 Meg on ADSL2+ even @ 6dB NM.

But we know there is some other underlying constraint, and finding it looks to be unlikely. We are just trying to tune what he gets in that situation.

In reply to a post by 4M2:

Bob,

Would one see an increased downstream attenuation with adsl2 compared to adsl1 on the same line? If so would it still be less than adsl2+ ?

As XRaySpeX says, no . There are lots of arguments about this, as some connections don't change at all, but what is known is that ADSL(1) and ADSL2 attenuations are always the same, given the same router. ADSL2+ can be the same, very occasionally lower, and often 2-4dB higher.

When it is higher, on 6Mbps and below, it seems frequently to be associated with a lower sync than ADSL2 gets. The argument tends to be about the cause and effect, but the result is observable.

Thanks for the clarification Bob

So the OP's adsl2 downstream attenuation would be the same with a adsl1 connection and the increased attenuation now reported with adsl2+ looks about right. Certainly I've heard that on a long line adsl1 can sync at a higher rate than adsl2+ (due to loop loss in the higher frequencies?) but is adsl2 more susceptible to noise than adsl1?

I haven't actually compared (same modem) ADSL an ADSL2 error rates. It seems to be accepted that ADSL2+ rates are higher. But if the sync speed of ADSL2 is the highest of the three, the throughput also seems to be the highest, therefore the error rate doesn't matter.

If it isn't the highest sync and throughput then it isn't the right choice. Simples . The reasons aren't too important, as long as home wiring has already been optimised.

Interesting stuff

One thing that I have discovered with adsl2+ (SMPF) is that if I resync at night I lose a few hundred downstream K (~13900 down to ~13450) yet attenuation and SN Margin stays the same (36.5dB and 6dB) but I get far fewer errors reported by the router (tg585 v7).

I feel happier with a slightly lower downstream sync (and corresponding throughput) with fewer errors and hence greater stability but this might be a total misconception?