wholesale checker accuracy

just wondering...

does the checker know how far the customer is from the cabinet, is it a measured figure, or is it a guess based on postcode or similar?

There is no known. Until u see on the BT FTTC Modem to tell u how far from cabinet.

Edited by adslmax (Mon 02-Dec-13 17:01:14)

so it is pretty much what our american friends might call a SWAG* then?



*Scientific Wild Assed Guess

What? That just doesn't make sense and the BT modem certainly doesn't know how far you are from the cabinet.

Please reread your posts to make sure they make sense.

In reply to a post by cookie:

just wondering...

does the checker know how far the customer is from the cabinet, is it a measured figure, or is it a guess based on postcode or similar?

It does indeed. It'll either use records of line length if you give the address or phone number, if postcode it'll base it on the property in centre of the postcode.

Please disregard his reply it's incorrect, and confusing at the very least.

The estimates are getting better, I'm guessing they are based on known information but BT will only know what info that is. Distance, line quality, allly or copper etc.

Going by recent posts I would suggest most people seem to get somewhere in the area where the two speed ranges overlap, but it comes down to distance, quality of line and any interference issues.

So the only real way to know is to try it, which is what adslmax probably meant.

Interestingly I just checked a neighbour's address. (They are on Sky). Reason being they have a serious problem, under 400kbps sync on ADSL2+!

On the same cabinet as me, it shows:-

FTTC Range A (Clean) 72.7 54.6 20 16.3 -- Available
FTTC Range B (Impacted) 62 34.9 20 11.4 -- Available

WBC ADSL 2+ Up to 3.5 -- 2 to 6 Available

Mine shows:-

FTTC Range A (Clean) 63.8 46.9 18.6 12 -- Available
FTTC Range B (Impacted) 53 29.5 18.6 8.4 -- Available

WBC ADSL 2+ Up to 4.5 -- 3 to 7 Available

given the number. Given the address the FTTC figures are the same as with the number, but the ADSL2+ is only 4Mbps.

I'm pretty sure that BT have records of the attenuation value for lines, at 300kHz - the documents that estimate the nationwide picture of line lengths give a reference back to some BT statistics based on such attenuation.

If that is true, and the estimates are based on the attenuation values, then they take into account length, diameter, metal-type and quality of copper.

In reply to a post by WWWombat:

I'm pretty sure that BT have records of the attenuation value for lines

What about lines that never had BB on them? Or even ones that never had BTw BB? Wouldn't imagine BT had attenuations for those.

In reply to a post by XRaySpeX:

In reply to a post by WWWombat:

I'm pretty sure that BT have records of the attenuation value for lines

What about lines that never had BB on them? Or even ones that never had BTw BB? Wouldn't imagine BT had attenuations for those.

My comment is based on section 2 of this Sagentia report for Ofcom. It states:

The main data required for this study was the statistical distribution of line lengths and
types for the millions of copper loops in the UK. We have obtained this data from
public domain sources.

and

A paper for NICC DSLTG by John Cook presents the cumulative distributions for BT’s
network of line length for exchange to customer and cabinet to customer in the form of
attenuations.

We know of attenuation being determined by DSL modems, and being tested by the diagnostic woosh tests. However, they aren't the only way in which attenuation can be figured - there are indeed single-ended line tests that can be performed at the exchange that give this result.

So it is certainly possible for BT to measure the attenuation of every line in the country, whether it has DSL or not. And we know that BT perform routine line tests every 24 hours too.

But whether they *have* performed tests for attenuation on all their lines is unknown.