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[banger]

What is the difference between these two estimates on the checker. There is a little note about Bridge Taps on an impacted line, first of all what is a bridge tap?

Secondly how do know if your line should be clean or impacted, surely openreach should know by maps of the line?

I am currently chasing my ISP to chase Openreach to replace my underground feed which I think they accept is sub standard and not twisted pair. But what about the rest of the line can you get a pair swap if the line is within the impacted range?

[Black Sheep]

1) Bridged taps is the posh term for star-wiring ........... basically extension sockets not connected through an SSFP

2) Cross-talk is as big an 'impact' as bridged-taps. This is not something that can be 'mapped' on a daily basis as EU's come and go from the FTTC service.

3) OR's remit is to not replace wiring speculatively. In other words, a fault should exist before this should be done. Your particular 'Figure 8' wire should be changed as it is obsolete and not to DSL specs.

[banger]

Many thanks for the clear explanation.

[WWWombat]

This is always tricky to explain.

First, your line is what it is. It either suffers from a fault, or it doesn't. There is either something wrong or there isn't. (OK, an intermittent fault pushes the boundaries, but I hope it is clear enough).

Second, the DSL checker only started to show 2 ranges when it became possible to perform self-install. That is an important thing to remember.

Third, the checker doesn't know if your line is faulty or not.

Fourth, that checker is really provided by BTW for ISPs to use, and isn't really intended for Joe Public. It has explanatory text there, but it doesn't seem to get treated as though it needs to be fully clear for even the most technophobic member of the public.

So, having said that...

What the checker does is provide two ranges for an ISP to use when offering to sell you a service.
- The A range is intended for use when you buy an engineer-installed service. The B range is intended for use when you buy a self-install service.
- Some ISPs use it this way, and some don't.
- Plusnet offer engineer installations, and quote the A range.
- TalkTalk offer self-install, and quote the B range.
- AAISP quote from the bottom of the B range to the top of the A range.

However, the ranges offered have nothing to do with the actual state of your line (at the time of ordering). Your line might be in a perfect state, and not be bothered by crosstalk - and you could get speeds faster than the A range, even with a self-install. Or your line could be terrible, and not currently able to get up to the bottom of the A range. The checker doesn't know.

What the ranges do instead is set the threshold at which Openreach will respond to a report of a low speed after the installation, and agree to send out an engineer to fix things. That is all.

That's important to remember for the future. If your line is perfect now, and you buy a self-install because it is cheaper, BT won't respond to future speed reductions until you go well below the bottom of the B range.

It is also important to remember when you migrate. Start with an engineer installation, and migrate to a self-install, and you might find your threshold has changed from the A range to the B range, and might (over time) have dropped in value too.

Finally, it is still important to remember they are only estimates. If, once the engineer turns up, he cannot improve the speed, then it could be left at that. The only real comeback you have available is to cancel.

That's how the ranges work, but not why they exist.
Why have two ranges?

When you pay for an engineer install, you aren't just paying for him to plug a modem in. You are instead paying for him to check that your line meets the standards for the A range, and to fix it if it doesn't. Openreach are thus assured that your line is working well, and they are happy to maintain it to this higher standard in future.

When you choose to opt out of an engineer installation, your line is going to run in an unknown state. Openreach don't have the same assurance that your line is in a good state, because no engineer has looked at it, and they aren't willing to commit to such high speeds.

I presume the thinking is this: If a self-install offered the same threshold, then a subscriber would be motivated to just order the cheaper self-install, and then get Openreach to send an engineer out 2 days later (at Openreach's expense) to get the line up to the standard that a (paid for) engineer installation would have done. Openreach, presumably, don't want to fund that.

[banger]

So where do I stand with a sub-standard underground feed of DW3 straight pair not twisted which was put in in the 80s and am just above the bottom of the B range?

[burakkucat]

I thought that Black Sheep has confirmed, in another post, that the wiring is not up to the specification for a telephony circuit and that it would be corrected, FOC to both your CP and yourself.

[banger]

I thought that Black Sheep has confirmed, in another post, that the wiring is not up to the specification for a telephony circuit and that it would be corrected, FOC to both your CP and yourself.

I have asked Uno to book Openreach but apparently TTB want to review the line data to see if it is necessary for an engineer visit I am guessing. I did try to downgrade my package to 40/10 on the first day but was met with a blunt TTB wont do that in the minimum term.

[Weaver]

@wwwombat - I didn't know that at all - about the engineer visit. That's really valuable, thanks. Is this stuff written up anywhere?

I wonder if I can buy an engineer install through AA? I hope so, that would be worth a huge lot to me. I haven't seen any mention of it though.

[WWWombat]

and am just above the bottom of the B range?

Please note: everything I said about the ranges applies when the *only* indication of a fault is the low speed.

Openreach also have automated line testing systems that can be run by the ISP, which ought to happen whenever you call to report a problem. If the line testing reports a fault, then Openreach will accept that indication even when the speed is within range.

I guess, from the mention of TTB, that you might be getting caught up because your only indicator is the speed?

So where do I stand with a sub-standard underground feed of DW3 straight pair not twisted which was put in in the 80s

In terms of getting the line fixed during an appointment:
I think Black Sheep has this covered.

In terms of getting an appointment:
I guess it depends on what kind of installation happened, what range you were quoted by Uno, and what the automated test results are.

And, cynically, I guess it depends on TTB playing ball.

I don't know that Openreach accept reports saying "Please replace this substandard kit you left me with". They need to be convinced the service is substandard.

[banger]

Engineer booked for 6th. Just had the ticket updated. Uno said Openreach had said there was an advisory on the line when it was DLM fastpath which the said was Interference at my property between 0600 and 0945, but since then this seems to have settled down, there are still errors on the line but since Interleaving and INP has been switched on this is a lot less.

My point is the house feed is single pair non twisted DW3 and not suitable for VDSL and is probably causing my fairly low sync. Range A was given as 80-66.2 range B is given as 76-41.8 I am getting 44. Uno control panel says expected speed is 66.2 but also states the two ranges and they don't do an engineer install I did ask.

[WWWombat]

@banger:
Fingers' crossed.

Is this stuff written up anywhere?

Some of it is in the (internal) FTTC handbook, but even then it isn't written with great clarity. And the internet can only provide you with old versions of the handbook.

I have versions 9, 10 and 12 of the handbook:
- Version 9 pre-dates self-install. There is no mention of the ranges
- Version 10 is the first update for self-install. It includes the text:

When customers order Self Install they should understand that there is a higher risk of the line being impacted with wiring issues and End Users getting lower line and throughput rates. We recommend that CPs use Range B Broadband Availability Checker (BBAC) values when providing estimated speeds to their customers.

- Version 9 mention two main ways that speed is affected: By distance, and by take-up (ie crosstalk).
- Version 10 adds a third category: internal wiring:

Any environmental issues within the EU premises (especially for Self Install Installations where no Openreach engineer visit is made to the EU premises)

However, there is no clearly explicit statement that the "A range" applies to the other types of install, where the engineer visits.

For the handling of faults within 90 days,
- Version 9 worked on a threshold of 50% of the predicted speed. Or a 25% drop within 14 days.
- Version 10 worked on a threshold of the bottom of the B range. Or a 25% drop in 14 days. (IMO they get it wrong to mention the B range here)
- Version 12 fixes version 10 by making the threshold at the bottom of the "point of sale predicted rate" instead of just being "Range B". However, they drop the threshold lower by specifying the 10th percentile, rather than the bottom of the range (which is the 20th percentile).Or a 25% drop within 14 days.

It is clear that the "point of sale predicted rate" is important. Just not clear which source it comes from.

However, the information I gave about about how Plusnet, TT and AAISP use the predictions comes from me running through their ordering system.

I wonder if I can buy an engineer install through AA? I hope so, that would be worth a huge lot to me. I haven't seen any mention of it though.

This all really applies to FTTC, though Weaver. Doesn't that make it more of a mental exercise for you? Or mental torture, perhaps?

[banger]

@WWWombat

Thanks. I think I have done all I can internally including a new Mk3 Openreach faceplate with extensions coming off the filtered part and no ring wire.

I just put my number in BT retail and they are guaranteeing me 60m downstream give or take 1 or 2 mbps so that must be engineer install? I am also sure in the Uno sign up process it said 66.2m as estimated speed and then the range so maybe they covered themselves with the full range 80-41.8.

[Weaver]

@wwwombat - ah. I was totally misunderstanding - the A and B ranges only apply to FTTC? No equivalent for ADSL2+ then ?

Thank you for your generous explanation by the way.

[NewtronStar]

yes when you think back to four years all FTTC installs were carried out by Openreach engineers as they supplied the magic box HG612 or ECI modem that was in the back of the van.

My question is what range does your ISP use when you had OR install FTTC four years ago because I've gone through 3 providers in the last 20 months and no engineer is required.