In reply to a post by dspillett:

IIRC the 80/20 product uses frequency bands spread over an 18MHz range were the slower product just uses a subset of those (over a range of about 9Mhz) - if your line experiences a good bit of signal loss in that subset of frequencies then you are going to get less than 40/10 on the 40/10 products but might still get more than 40/10 on 80/20 products (but not the full 80/20) because the extra usable bandwidth in the other frequencies makes up for the deficiency in the other bands.

I do not believe that is true. AFAIK both products use the same frequencies and have since the change to 17a, one has a 40/10 sync cap, the other has an 80/20 sync cap.

In reply to a post by kasg:

I do not believe that is true. AFAIK both products use the same frequencies and have since the change to 17a, one has a 40/10 sync cap, the other has an 80/20 sync cap.

I was working on the impression that only the faster lines were using 17a, though I could easily have grasped the wrong end of the stick. Having a sync cap would be easier to manage than having two sets of customers on different standard versions, so probably makes more sense.

Edited by deleted (Tue 14-Aug-12 14:18:19)

In reply to a post by dspillett:

I was working on the impression that only the faster lines were using 17a, though I could easily have grasped the wrong end of the stick.

No, everything has been on 17a for some time now - last year I think.

Yes, I've been on 17a for a long time, on a 40/10 then a 40/2. Currently 80/20.

I started on the 40/2 8c profile in June 2011.

I was auto-switched to the 17a profile in October 2011.

I experimented with the 80/20 trial service with my ISP Plusnet, but there was no speed increase whatsoever, so I reverted to the 40/2 service after a couple of weeks.

Strangely (or not) my connection initially achieved higher speeds using fewer available tones on the 8c profile than it does on 17a.

Crosstalk from increased numbers of users may have restricted my achievable sync speeds.
I believe I was one of the first users (if not the first user) to be connected to my cabinet.
For the first month or so of being connected, BT were still claiming FTTC was not envisaged in my area during the next 6 months.
My original Plusnet speed estimate was 14.6Mb & I achieved 33Mb actual throughput until lots of physical issues messed everything up.

I am too far from the cabinet (attenuation-wise) to utilise the highest frequency band & can only use part of the middle frequency band.
I can use all of the lower frequency band.

My current & stable connection sync speed is around 28Mb & was up to 35Mb on the 8c profile.

I have asked if it is possible to revert to the 8c profile (as an experiment for sub-40Mb connections).
However, it is not currently possible to do that.