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FTTC saga - fact check?

et0 — Tue, 28 Jul 2020 16:50:45 GMT

Hi all, looking for some guidance - I have very poor ADSL speeds due to the distance to the exchange (at least 3 miles away). It's 2MBps down and 0.5 up on a good day and highly erratic, which just isn't good enough in this day and age of video conferencing and working from home.

There's a new FTTC box recently installed 80 metres away to which all my neighbours are connected. Using any broadband provider's estimate page I see they can get e.g. 40MBps speeds, even to a caravan on the next farm.

Openreach refuse point blank to re-route my connection or provide a new line (even paying whatever it costs) to the new FTTC box. Even after getting my MP involved. As an electronics engineer I am perplexed by the reason given and would like an expert opinion on what is going on here:

Extending the network to our newer cabinet and back to -----'s property would have an
adverse effect on existing ADSL/voice services currently provided over our copper network. When
we deliver fibre services – in this case FTTC - it can’t be done at the detriment to existing service on
our copper network. With this in mind we can’t re-route ----- into our newer cabinet near
her home, as it would have a negative effect on the other lines using the same cable route.
This is known as back-wiring and there are also Ofcom guidelines against us doing this. I’m really
sorry but as simple as it looks it just isn’t how broadband and our network functions and not
something we can do.

The same letter then goes on to advise applying under CFP to get full fibre - apparently then it would no longer a technical problem? However, since CFP requires a community effort, not just one property, that's also a dead end because all our neighbours have broadband that they're happy with.

Can anyone explain what "back wiring" means and how running a new copper pair to a different DP would adversely affect other voice connections?

Thanks!

Re: FTTC saga - fact check?

licquorice — Tue, 28 Jul 2020 17:12:29 GMT

It will be due to running a high powered VDSL signal with an inappropriate PSD mask amongst ADSL signals causing them crosstalk problems.

Re: FTTC saga - fact check?

et0 — Tue, 28 Jul 2020 17:36:00 GMT

Thanks licquorice!

OK. I thought the idea of PSD was to moderate the spectrum of VDSL precisely to avoid crosstalk problems? Or can it not be tuned per individual connection?

Could this be solved by running a new cable the 80m along a verge to the cabinet - maintaining separation from the ADSL bundle? That's basically what I've been asking for.

Re: FTTC saga - fact check?

licquorice — Tue, 28 Jul 2020 17:37:41 GMT

As far as I'm aware, the PSD mask is calculated on a per cabinet basis for all circuits in the cabinet. A separate cable would possibly obviate the problem but I don't know the logistics and feasibility of doing that.

Re: FTTC saga - fact check?

et0 — Tue, 28 Jul 2020 17:45:18 GMT

OK, got it.

I think that's what we keep coming back to. It looks very straightforward to run a new cable, even if it can't use the same duct.

Openreach obviously don't want to spend any money upgrading anyone if they can avoid it, so they've deflected with this technical reason. But I'm offering to pay.