In reply to a post by partial:

I would imagine that heavier poundage cables are towards the end of a run on local main cables. Duct space at the exchange is at a premium.

I kinda agree here, at least in the general case.

However, this cabinet is already 6.5km from the exchange, leaving no allowance (in resistance/attenuation terms) left for the D-sides. At least some of the E-side must be thicker than 0.5mm.

Of course it could still be only in a part towards the end of the E-side, as the available duct space is likely to come under less pressure there.

However, aren't the E-side cables pressurised? If so, how does that system cope with joints within the E-side?

I doubt you would find a 0.7mm cable anywhere in the UK.

I could have sworn I had seen plenty of UK-spec cable at 0.7mm, but it appears otherwise. I wonder what made me think 0.7mm was in the inventory?

The only thing leaving the exchange at 0.9mm is likely to be a junction which may drop off and feed punters in remote areas but is highly likely to have loading pots on.

I'm not sure what you mean by "a junction which may drop off", but a 9km line certainly suggests a remote feed.

It is good to see someone getting a service at a distance.

I think the longest I have ever heard of is reportedly 4.2km: see this plusnet thread.

One extra word: It used to be the case that long lines would be limited by the upstream availability first. I'm not sure if BT have since altered settings which allows the distant modems more of a fighting chance; for example with different UPBO settings, or different bitloading algorithms.

Distance of the cabinet from the exchange is also a factor, as different power masks are used to avoid destroying ADSL/ADSL2+, which may explain the variation in what are thankfully a small sample size of very long lines to cabinets.

Useful information would be your IP Profile. (I think Timico use BT Wholesale so there will be one). Multiplying the IP Profile by 1.033 gives the sync speed within a few kbps.

Comparing that with your estimates and actual throughput speed would be interesting.

BTW Performance Test. For now, ignore the red instructions and just say you've followed them. At the bottom of the initial results page click the Further diagnostics button.

Please copy and paste the full contents of the two text boxes of results. We don't need to see the graphics.

A word of caution based on the experience of a neighbour who is a few hundred metres closer to the cabinet...

After getting an initial speed of 7Mbps down and 0.5Mbps up with a ping of nearly 100ms, my neighbours service failed within the day and despite Openreach spending several days working on this, he was eventually told that BT couldn't support FTTC for his house (too far away from cabinet and on the worst of the 2 bundles of cables that come to our village) so he would have to go back to ADSL...

Meantime my service seems quite stable at what I suspect may be one of the slowest 'Superfast Broadband' FTTC speeds in the country... 3.1Mbps down and 0.9Mbps up - but this is the maximum that the line will support.

I think the thing that I learnt from this is that if your ADSL was 'ok' before (I had 1.9Mbps down / 0.3Mbps up) then you 'might' see an improvement - otherwise don't bother and look for a non BT based alternative.

Perhaps the most useful change seems to be the one yet to be announced - the possibility of ADSL2+ from the cabinet.

I have read this thread in the past when I was thinking of ordering FTTC as my line is approx 6km long, the cabinet reduces my line length by about 3km.

Had BTO install FTTC yesterday, it connected at between 4Mb and 8Mb but it would not stay connected, the BTO person suggest this implies a line fault and after trying to swap pairs and rule out other obvious things, he has put me back to ADSL and raised this as a fault. The JDSU showed my line to the cabinet is now a 36dB attenuation and claims the line length is now 1.9km.

Waiting to hear what BTO and PlusNet say are the next steps.

But ... what happened to the people in the thread on long lines, did they ever get resolved?

In reply to a post by WWWombat:

... ADSL2+ from the cabinet.

OK so if ADSL2+ from the Cabinet is available at the same cost as Standard Broadband that would be great.

But everything I have read states that at long distances VDSL2 and ADSL2+ have the same performance. So if VDSL2+ has problems working on these long lines then so should ADSL2+.

Vdsl2 can work great on short loop lengths but rapidly runs out steam from about 400m onwards, where as ADSLx will work for several km, even from the cabinet it should have considerably more range than VDSL 2, otherwise there will be no point.

In theory, VDSL2 can extend reach in the same way as ADSL2+, when unhampered.

In practice, VDSL2 runs out long before ADSL2+ would - and it seems to be the upstream side that is lost first.

I suspect the reasons come down to something related to power - either:

a) The extra PSD mask that restricts transmit power at the cabinet. Which, for the lowest frequencies with the potential longest range, causes the FTTC cabinet to transmit at a reduced power level. In the end, the signal will be received at the same power level as though it came from the exchange, not the cabinet!

b) The fact that VDSL2 has upstream bands above U0 that most subscribers rely on, means that U0 can be transmitted at lower power ... helping to make sure it doesn't crowd out ADSL2+ upstream. I don't know whether that affects the longest lines or not, but it could...

The need to work in a network that also has to support exchange-based ADSL is what hampers VDSL2 in practice.