Annex A or Annex B

Hi,

I have now used BT Infinity 2 for a number of years now and I tend to set my router to use Annex A because the BT Wholesale line checker appears to indicate that Annex A was the best for my phone line.

About six months ago, we moved house, and it took a few months, (and a visit from a BT boost engineer), for BT to get the connection up to scratch but I was still only getting about 39 mbps down and 8 mbps up instead of the 80/20 that I was paying for but it was generally an OK connection so I was not too unhappy with it.

About two months ago I needed to speak with BT about their usual monthly billing mistakes and I pointed out that I was not happy paying for an 80/20 connection and was effectively only receiving a 40/10 connection; I also pointed out that new customers were being offered cheaper deals and I negotiated the same phone and broadband package at the lower price that was being offered to new customers. (ie. still being on BT Infinity 2 but paying the cheaper prices applicable to new customers pay): so far so good.

It could be an unfortunate coincidence but on the exact day that the new billing charges kicked in, (for exactly the same phone package and exactly the same broadband package),, for some inexplicable reason my line dropped and restarted and I found that my connection was inferior and was much slower with some line noise but a BT engineer said that he could not find anything on the day he called.

For most of the time that I was on BT Infinity I used a Fritzbox 7390, (which was set to Annex A), and was generally happy with it but just before the change over I sold my two year old reliable Fritzbox 7390 and had I bought one of the new Fritzbox 7490 systems, (which arrived just after the billing change date and I was an extremely disappointment because the DECT phone performance still stank and the wireless connection was unreliable with intermittent problems. - I sent that new router back for a full refund, which I eventually received, but I was not at all impressed by the Fritzbox approved distributor that I bought it from or the backup provided by AVM/Fritzbox but that is another story.

I was then left using the fallback BT Homehub 5, that I had bought as a backup in case I ever had line faults and since the BT Homehub 5, (which generally not a bad router), does not provide a lot of line stats/information I have no idea what Annex that was on.

A few days ago I bought a new ASUS DSL-AC68U router and I set it up to use Annex A but it tells me that it is on Annex B.

The BT Wholesale Line Checker for my phone line indicates that both FCCT Range A and FCCT Range B are available for my line and that FCCT Range A is "clean" and FCCT Range B is "impacted".

How can I get it to choose Annex A ?

Does this matter?

Fido

What is this Annex A your refer to?

Is it the Range A indicated on the BT Wholesale checker?

You cannot get you modem to work on either of the ranges - they are just guestimate for line performance. Range A is for a near perfect line with minimal noise, whereas Range B is the suggestion of what you might see if there is crosstalk, high background noise or imperfect wiring.

As MHC says. The "Range" on the BT Wholesale estimator is the range of speeds you can expect on your line, depending on the condition of it all the way from the exchange on ADSLx, through many junctions and whatever, and on the same from the FTTC and PCP cabinets to which you are connected on FTTC. The stretch from the cabinet to the exchange is eliminated.

Clean means what it says, a line in good condition for the whole of the respective distance. Impacted is for when there is something sub-optimal. For instance an engineer install of FTTC would be to the master socket, with the user modem or in the case of Infinity these days the Home Hub connected by a short cable to that. An optimised setup, unless the external wiring is suspect.

A self-install is likely to be at an extension, and house wiring between master and the extensions is often sub-optimal. Simply having poor wiring generally results in lower speeds even when using the external socket of the master. An impacted setup, whatever the condition of the external wiring.

On ADSLx this could easily make a difference of over 1Mbps until the wiring was improved, and sometimes over 2Mbps. On VDSL2 (FTTC) it is far worse due to the much greater range of frequencies in use.

"Annex" is a totally different thing, to do with the frequency ranges available. In this country ADSLx runs on Annex A and optionally (a provider setting) Annex M. FTTC uses Annex B. Your modem should be set to that, and PTM mode.

Edited by RobertoS (Wed 21-Jan-15 14:55:59)

The BT Wholesale checker does not make any recommendations over which mode of VDSL2 to use.

Annex A and Annex are referring to whether you are using xDSL over a POTS (the UK) or over an ISDN line (e.g. Germany).

Generally leave the router set to AUTO in terms of negotiating the xDSL variant for it to use. On the new Asus router, check for newer firmware versions.

On the not getting 80 Mbps, how far are you from the cabinet.

Clean refers to what speed Openreach estimate if there is no issues with the line.
Impacted suggests what might be the speed if there are issues with the line, or you are using microlilters and the modem is on an extension etc

In reply to a post by MHC:

What is this Annex A your refer to?

Is it the Range A indicated on the BT Wholesale checker?

Yes.

In my, (now obvious), ignorance I was confusing Range A and Range B as indicated by the BT Wholesale Checker to be a form of Annex A and Annex B as provided as a choice in the router setup menu.

In reply to a post by MrSaffron:

On the not getting 80 Mbps, how far are you from the cabinet.

I would not expect 80Mbps as I am about half a kilometre from the cabinet via the road route,

That said; I do expect a fast snappy connection and since the inexplicable line reset that occurred on the billing change day the line performance has been inferior and I was looking for potential reasons for that deterioration.

eg. I have had a voice call noise issues and even a few voice call dropping issues after the billing change reset and these noise problem were still there when I plugged a wired handset into the master socket behind the face plate but the BT voice line engineer could not find any problems during his visit but since his visit is has been a lot better.

In reply to a post by MrSaffron:

Generally leave the router set to AUTO in terms of negotiating the xDSL variant for it to use. On the new Asus router, check for newer firmware versions.

That is what I now plan to do as the new Asus DSL-AC68U Router seems to be working well and I had already updated to the latest firmware as soon as I plugged in in and switched it on.

I will give the new router time to settle as it seems to be a good choice.

Regards,
Fido

The VDSL standards
� Annex A is Asymmetric BandPlan
� Annex B is Symmetric BandPlan
� Annex C is Fx BandPlan
Annex C is not for the UK

This has nothing to do with the range, the range is done by the SALT tester (Subscribers Automatic Line Test) which has a SELT and DELT parts � the SELT is for when you don�t have equipment on the end and the DELT is for when you have termination equipment. This feeds into the AWS which sets your Profile and Spectrum, which determine what service you get.

VDSL, or VDSL2, or both?

Openreach GEA FTTC is VDSL2 Annex B, and the band plan doesn't look symmetrical to me. Unfortunately away from home and on ADSL2 so can't give you mine.

Just out of interest, what led you to wake up a thread that was born and died on one single day in January 2015?