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Plusnet VDSL2

G3YBO
Grafter
Posts: 103
Registered: 27-11-2010

Plusnet VDSL2

Can someone tell me which VDSL2 profile Plusnet/BT are using..............
Thanks
Roger
6 REPLIES
prichardson
Grafter
Posts: 1,503
Registered: 05-04-2007

Re: Plusnet VDSL2

Can't find the answer for this unfortunately, which probably is not help by the fact you cannot access the modem.
Not sure of the need to access this detail though, given that under the ANFP, the service is restricted to 40mbps, so not even reaching the base 50mbps.
From looking on all the research data used across the industry (public data BT Exact from 2001 and other public sources outside of BT & Ofcom), I suspect either 12a or 12b is in use. This is based around the information that frequencies upto 12Mhz will be used.
G3YBO
Grafter
Posts: 103
Registered: 27-11-2010

Re: Plusnet VDSL2

Hi Phil..................Ok thanks for that.......Reason is I need a RF filter on the modem input.....The one I have been using was
up to ADSL2.....This now cuts speed down to 10Mb, as filter will only pass up to 4.3Mhz.....So if it is 12a or 12b thats the answer.
Regards
Roger
Community Veteran
Posts: 1,411
Thanks: 4
Registered: 29-01-2009

Re: Plusnet VDSL2

IIRC, BT have opted for the lowest power, lowest bandwidth profile - which I think is profile 8b.
This is a profile specifically design for cabinet use, and I think the point behind it is to reduce crosstalk - either to other VDSL users, or (morlikely) to ADSL2+ users in the same wiring bundle.
I did have details, but this laptop won't read PDF's, so I can't check...
Plusnet Customer
Using FTTC since 2011. Currently on 80/20 Unlimited Fibre Extra.
G3YBO
Grafter
Posts: 103
Registered: 27-11-2010

Re: Plusnet VDSL2

Hi  WWWombat.........Thanks for that, I do have details of the profiles but just needed to know which was in use......One thing
a much better service to me than Adsl2........Had it about two weeks now and it works well.......Holes all over the area by BT
followed by the Gas people......
Regards
Roger
Community Veteran
Posts: 1,411
Thanks: 4
Registered: 29-01-2009

Re: Plusnet VDSL2

Quote from: WWWombat
IIRC, BT have opted for the lowest power, lowest bandwidth profile - which I think is profile 8b.

Right, I'm back on the PC with access to the PDFs, and it looks like I was right with the principle, but wrong with the profile...
There's an Openreach document that mentions profile 8c as being specifically for cabinet deployment, but doesn't explicitly say that it is the profile they will be using. It's a good primer on VDSL, even if it rests on information dated 2009.
It does show that the UK ANFP specification allows VDSL2 up to 7.05MHz from the cabinet, but not from the exchange.
This means the UK is using a truncated version of the 997 band plan:

  • D1 - 138kHz to 3MHz

  • U1 - 3 MHz - 5.1MHz

  • D2 - 5.1MHz - 7.05MHz


In a separate document from Ericsson, I can see that this frequency pattern matches profile 8c. The power levels are:

  • 8a - 17.5dBm

  • 8b - 20.5dBm

  • 8c - 11.5dBm

  • 8d - 14.5dBm


So, the lowest bandwidth, lowest power variant is profile 8c, on a truncated 997 band plan.
Plusnet Customer
Using FTTC since 2011. Currently on 80/20 Unlimited Fibre Extra.
G3YBO
Grafter
Posts: 103
Registered: 27-11-2010

Re: Plusnet VDSL2

Hi WWWombat................Thanks for that, great info indeed...............Regards................Roger