FTTC / VDSL2 trial

[#1]

@orbrey:  Thanks for the confirmation Matt - that's what I thought.  If I want to get the promised 20Mbps or whatever, then I'll have to buy a VDSL2 box, and get Plusnet to sort me out a VDSL2 service to it.  Otherwise I can still carry on using my ADSL modem at the same old speed.  I couldn't see this spelt out in black and white anywhere.  I'd naively assumed that the fibre would carry the data to the cabinet, and then it would be converted to ADSL, which would deliver a significant improvement in speed for me (because my copper length would reduce from over 6km to just a few hundred meters).  I didn't realise it was a whole new technology.  Apologies for being so thick...... 

[#2]

It would seem to be the sensible option - then they wouldn't have to install special boxes in peoples houses.
Surely 20Mbps is enough for most people?

[#3]

Quote from: dunbankin

I'd naively assumed that the fibre would carry the data to the cabinet, and then it would be converted to ADSL, which would deliver a significant improvement in speed for me (because my copper length would reduce from over 6km to just a few hundred meters).  I didn't realise it was a whole new technology.  Apologies for being so thick......

Not naive at all - you have hit the nail on the head.
FTTC is simply moving the reach of the fibre backhauls closer to your home, which also necessitates moving the ADSL termination equipment closer too (which in turn requires a bigger cabinet)
The difference you as an end user will notice is a lower attenuation, and higher SNR - entirely down to the fact that your copper is shorter.
You should also notice a decrease in latency, since copper is far slower at transmitting an electrical signal than fibre is at  transmitting light.
The presentation of your service should remain just the same though.

[#4]

@James_G:  Aaaaah!  It's all becoming clearer to me now.  I'll have two choices:
1) stick with my existing ADSL modem and service, no change whatsoever, and gain an instant boost from 1.75Mbps to 4 or 5 or whatever, without having to ask PN or BT to do anything, due to the shorter copper length,
or
2) ditch my ADSL modem, get a VDSL box, get PN to arrange a VDSL service to it, and see speeds of 10 or 20 Mbps or whatever.
Niiiice.....!
Thanks
John

[#5]

Just found this very useful tutorial about VDSL, which others might find as informative as I did:  http://www.iec.org/online/tutorials/vdsl/index.asp.
Enjoy!

[#6]

http://www.thinkbroadband.com/news/4011-aaisp-connects-first-business-on-bt-fibre-to-the-cabinet-pil...
This makes it sound like BT are providing the Modem for VDSL2 to which you can connect your existing router to.

[#7]

@Bojangles:  Yes, but only for the current two-exchange trial.  I doubt they'll be so generous when it comes to national roll-out next year...............
I seem to remember reading somewhere that they will be "exploring" some sort of self-install product. 

[#8]

Quote from: James_G

You should also notice a decrease in latency, since copper is far slower at transmitting an electrical signal than fibre is at  transmitting light.

I would have to mighty quick to notice that!
The speed of light is inversely proportional to the refractive index:
Refractive index of copper: about 1.1
Refractive index of glass: about 1.3-1.5
So it travels slower in glass
But since it travels in the region of 300,000 Km/sec - I don't think it matters much.

[#9]

Quote from: dunbankin

Will I see any speed improvement from my existing ADSL modem, or will I have to get new kit (a VDSL2 modem?) in order to see any speed increase?

BT install a VDSL2 modem, the ADSL modem will no longer work. Eventually it will become a self install product so you'll buy your own VDSL2 modem but for the trial BT come and install it and supply the kit.

Quote from: dunbankin

If BT are jamming a VDSL2 signal down the same copper wire as the ADSL signal, surely there'll be less bandwidth for the ADSL signal, hence lower ADSL speed?

They turn the ADSL off when you get upgraded to FTTC, you can't have both at the same time.

[#10]

Quote from: Crucibleofevil

How do telephone calls work on this system? Is it a parallel system in copper, or is it multiplexed onto the broadband signal?

Phone calls aren't changed, you have the copper line to the PCP (green cabinet) as you do now from your house, in the cabinet is the VDSL2 DSLAM which splits the voice and broadband like the MDF does at the exchange, voice stays on the copper and broadband is carried over the fibre.

[#11]

Quote from: Crucibleofevil

Being a bit thick here - but presumably these FTTC exchanges will also have to roll out voice over WBC?

Nope, this is broadband only, doesn't affect voice so doesn't need to have the PSTN 21CN switchover done yet.

[#12]

Quote from: dunbankin

@James_G:  Aaaaah!  It's all becoming clearer to me now.  I'll have two choices: 1) stick with my existing ADSL modem and service, no change whatsoever, and gain an instant boost from 1.75Mbps to 4 or 5 or whatever, without having to ask PN or BT to do anything, due to the shorter copper length, or 2) ditch my ADSL modem, get a VDSL box, get PN to arrange a VDSL service to it, and see speeds of 10 or 20 Mbps or whatever.

Unfortunately not quite. It's more like
1) stick with my existing ADSL modem and service, no change whatsoever, and no speed increase as FTTC only works with VDSL2 not ADSL
or
2) ditch my ADSL modem, get a VDSL2 box, get PN to arrange a VDSL2 service to it, and see speeds of 10 or 20 Mbps or whatever.

[#13]

I fail to understand why the ADSL signal can't be sent over fibre, then coupled into a short length of copper and delivered to me.
I know I wouldn't get 50Mbps - but I'd be happy with "only" 15 - 20 Mbps.
Sounds a bit daft that BT are going to maintain CTTC (Copper to the cabinet) in parallel with FTTC

[#14]

@dave:  The mists have finally cleared.  The penny has finally dropped.  Thanks for this.  I now understand that BT only send your data down the fibre to the cabinet if you've upgraded to a VDSL2 service.  If you stick with your old ADSL service, your data still has to trudge all the way from the exchange over copper.  I'd previously got the impression that EVERYBODY's data went down the fibre to the cabinet.
Got it finally.  Sorry for being so slow....
Regards
John

[#15]

Figures 2 and 4 found here may add more light.
Edit: Page 8 is worth a read regarding Power and Power Cuts.