OT - BT testing 800Mbps broadband

[Jabba]

BT has conducted field trials that show it can deliver broadband download speeds of nearly 800Mbps using fiber and copper, a company announcement said yesterday. The technology delivers data over fiber from the British telecom's facilities to neighborhoods while using copper for the final meters. Deployments of this sort are less expensive than fiber-to-the-home because they reuse existing copper lines used for telephone service and DSL.

These are greedy bastards who reckoned we'd never get anything faster than dialup speeds at home.

[Tim Watts]

So it's a tweak on FTTC with the fibre getting a bit closer.

[polygonum]

Funny how everyone seems to blame copper for slow speeds over the last few metres. As if the element itself were somehow the cause! Despite that fact that we have 100 Gbps copper connectivity using Ethernet. And gigabit copper appears everywhere these days using standard patch cables.

Certainly the POTS copper cables have lower limits, and the very fast Ethernet uses some fancy cables. But don't blame the element.

[Adrian]

Not 8km long, though.

[polygonum]

Nor was the story about 8 km.

"Speeds over copper degrade over distance, but BT said it was able to achieve 786Mbps download speeds over 19 meters and 696Mbps download speeds over 66 meters."

Which do not even reach the Cat5e 100m limit.

[dennis]

When they said that it was true. Things change.

The main thing to change is customer expectations, now BT can dump bits of the exchange in street cabinets and actually get away with them breaking and disconnecting a couple of hundred customers which they couldn't do in the past. Once you do dump stuff in the street you can use different technologies.

[Andy Bartlett]

100 Gbps? Really?. I think you mean 100 Mbps. Faster than that - 1 Gbps and up uses multiple lanes on copper cable due to skin effect and radiative losses.

Faster than that you need waveguide or modulate a light beam and use fibre.

[dennis]

But gigE uses four pairs, BT only have one pair. If BT were able to run in new cat5 cables it would be easy to just put a gigE switch in. In fact I suggested it to Vallance about seven years ago. It was declined "they would f'ing crucify us if we put new copper into the ground" was the response. The main reason for not putting fibre in is because the BT installers are likely to break it, it just isn't robust enough to bury in the gardens and such. That's why Virgin's fibre network uses copper to the home.

[Andrew Gabriel]

Your phone line is just 1 pair. When using ethernet, 100Mbits/s uses

2 pairs and 1000Mbits/s uses 4 pairs, and in both cases the pair quality is much more consistent than you will find in a 50 year old phone line which was designed for use at up to 4kHz.

I was working on ISDN during the development and roll-out, which was the first local loop data technology. That called for 160kbits/s data rate on the local loop. That was still impossible when the spec was written, but it was expected that within a few years people would work out how to do it in a cost viable way. The very first ISDN deployments still happened before 160kbits/s was achieveable and operated with just one B channel, or with the second B channel running at only 8kBits/s instead of 64kBits/s. Eventually, the technology caught up, and 2B+D+overhead = 160kBits/s was achieveable.

[F]

Someone tell the Merkins it's *metre*.

I suppose we have to accept that they can't spell neighbourhood and fibre correctly but, when it's an SI unit with a clear derivation for its spelling, there's no reason for the United States Government Printing Office Style Manual to invent its own 'standard'...

[Adrian]

No, but that's what BT cables have to deliver across. "Last few metres" my hairy arse.

[eastender]

Nice note and takes me back too.

I wonder if Ofcom will ever enforce sharing with the cable network conduits - it's madness to have this infrastructure and then make DSL run over old lines and poles, and in my case through two trees, under a new build development where water has got in, and more, when the cable and BT cabinets are side by side at the end of the road.

E.

[Davey]

Dream on....... they do things their way. They have always spelled it 'meter', they aren't going to change now. Their Spellcheck will make sure of that.

[Reentrant]

We don't blame copper round here. We blame aluminium.

[polygonum]

So what? It could use a million pairs, it would still be copper.

[polygonum]

My point was not the configuration of the copper (age, number of pairs, etc.) but that it *is* copper.

The use of "copper" is so often a lazy shortened form of "single pair of telecom grade copper wires and quite possibly laid a long time ago".

As has already been mentioned, Virgin cable use copper as well.

[polygonum]

However their claim for fantastic data rates was limited to short sections. They do not appear to be claiming they can achieve near-gigabit speeds at 8km distances.

[polygonum]

I decided to avoid complicating my point - but having dealt with quite a few customers on aluminium over the years, it was in my mind to point that out.

[Tim Watts]

I remember sometime in the early 80's or late 70's the GPO needed to add an extra digit to our numbers.

They did it over a weekend. Emergency calls would still work but dialling normally would not.

I think there were a couple of hours where nothing worked.

This was planned and communicated like a military exercise and probably took a year to plan at their end.

[Tim Watts]

Usually IME they have 2 pairs available in many houses.