The real reasons we have to wait for BT’s fibre-to-the-premises broadband
“Fibre-to-the-Premises rolling out next year!” scream the headlines. It sounds so easy. But wait: most people will have to be patient, with fibre not arriving until 2012 for many, and 2015 for many more.
Why, you might well think, do I have to wait that long? I was despatched to one of BT’s FTTP trials in Milton Keynes to find out how much work goes on behind the scenes, and this blog post will reveal everything you need to know — probably more than you ever wanted to know — about the labour put in by engineers to get a tiny little cable to your home.
Two things to keep in mind: first, Milton Keynes, being a newish sort of place, has a well-planned duct system, making the trial a bit more straightforward than it could be in other locales. FTTP in older cities won’t be so easy or even possible, while others will get fibre access over telegraph poles instead.
The other thing to remember is this: fibre is really, really thin. Surprisingly so.
The fibre in that picture isn’t the coloured bits — it’s the thin, hair-like strand sticking out of the end. The coloured material is to protect the delicate fibres.
The trial requires all-new cabling and the use of subducts, where the fibre is squeezed in alongside existing infrastructure. While keeping cables small is easier with fibre because it’s so thin, that also makes it breakable, so protective cables need to be thick enough to keep the fibre safe.
From each exchange in the test area in Milton Keynes, cables with a dozen fibres feed out to a splitter. There, each is fibre is spliced and split out to supply 32 customers — although BT usually keeps two aside for backup. The fibre winds its way through tubes in subducts to a local distribution point and a device called a manifold, which shares the fibre connection out to up to a dozen properties, but usually about half that.
(See that little hole in the wall at the top of the picture? That’s where all the cables need to go through. The device on the left with the cables feeding in is the distribution point, while the black tube on the right is a manifold.)
If the thinness of fibre makes it seem easy to handle, don’t be fooled. All the cabling is pulled through ducts by hand: no machinery can do it properly. That’s no small thing, as in the trial area in Milton Keynes alone, there’s 600km of cables as well as 4,000 manifolds and 1,000 distribution points to install — all to bring fibre broadband to 11,500 homes. Even if you don’t know what all that equipment is, the point is there’s a lot of it.
The fibre isn’t in the cables when it’s pulled through, however. The fibre cables are blown through the duct tubes using compressed air. Because this can be done over some distance, and BT would rather not shell out for a engineer just to stand at the end of a tube and wait for fibre to slide out, the system texts the engineer when it’s time to stop blowing, so the right amount of fibre is sent through.
(Fibre after it’s blown through a tube. Exciting times.)
All these bits of fibre — from the exchange to the splitter to the distro point to the manifold and then to the premise — need to be connected up. This is called splicing, and is rather like gluing together the ends of two pieces of hair. The engineer carefully strips off the fibre’s protective coating, exposing the actual fibre — which is easy to break and easy to get lodged in your skin.
The exposed fibre is cleaned with rubbing alcohol — the engineer actually listens for a squeak to make sure it’s clean — and the ends cut so they’re square, before being slid into a small box called a fusion splicer, which lines everything up and joins the ends. Watching the screen (see the picture below), shows the fibre ends being adjusted up and down until they line up perfectly, before the screen is filled with a satisfying sci-fi blast of white light, and the pieces are fused together.
BT tolerates a loss of up to 0.05db in the splicing process, but this machinery is so handy to use that I managed to join two pieces of fibre with just 0.03db loss on my first — heavily-coached — try.
When BT rolls out FTTP, it installs fibre from the exchange all the way down to the manifolds, but pauses there, only installing the last several yards to the house once the customer has coughed up the cash. “We’ve got to give the facility to every house,” noted one BT engineer. “It sits there dormant until such a time as a customer puts his hand up and says ‘yes, I want it’.”
Once the customer opts for the FTTP service, a specialised engineer comes out. Over the course of seven hours, he or she blows fibre through to the customer’s house, splicing the fibre to an external connector attached to the side of the customer’s wall, which connects to a lead internally to the “optical network terminal point” inside the house — essentially a BT-branded box with (hopefully) blinking lights and ports to plug a router into.
And if you’ve got one of these in your house, consider us jealous, because it means you’ve got BT’s FTTP.