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[Chrysalis]

kitz the difference could be huge.

if BT opted for line card based vectoring, and then did not organise the pairs so the bundles were split across different cards, then that would mean vectored lines would have neighboring pairs which arent vectored by the same card.  Given BTs record of maintaining local loops (not been very good) I would be surprised if BT put the time and effort in to ensure each pair bundle was all on one line card.

[kitz]

then that would mean vectored lines would have neighboring pairs which arent vectored by the same card.

Its my understanding that line card based vectoring just would not work in the above situation. 
If line card vectoring is used then all pairs from the same feed have to be on the same card, you cant mix and match. All must be vectored the same.  It could become cable hell and why they'd physically need someone to swap things round. 

I would be surprised if BT put the time and effort in to ensure each pair bundle was all on one line card.

Indeed, and this is why I think they may in the end have to either install the module which does the mapping for vectoring...  or in the case of the ECI's to upgrade the dslam. :/

[Chrysalis]

yep mixed cards on same bundle wouldnt work (unless shelf solution) thats why I think it would be more than a minor issue.

If it is true that they have halted ECI on new exchanges this in theory does at least reduce their replacement costs.

Both tbb and ispreview asked openreach if the vectoring trials are happening on ECI at all, both seemed to have not posted a reply to the question.

[JGO]

Recently saw an irate posting in another forum, saying that "fibre" should have a warning that the speed is very much "up to ---"

Is this true for FFTP ? and if so why ?

My understanding is that optical fibre has a loss below 1dB/km (0.6?) and this is not frequency selective as data is modulated on to an optical carrier wave.  From memory, the launching loss is a few dB so it wouldn't seem a S/N problem to have say a 10 km line ?   
(If you use FFTC and  adulterate Pilkington's nice fiber with copper  well that is a different story !!! )

[c6em]

He is correct in a sense
....Because all consumer lines are contended - or shared
Needless to say the FTTH fibre companies will not be advertising this point

Take a mythical village all 100% on FTTH.
So regardless of the fact that everyone's lines in the village say have the capability of receiving a 50Mbps service at indeed 50Mbps 100% of the time - in actuality because the backhaul links to the village cannot handle EVERYONE downloading at the full 50Mbps rate, then at busy times you will get slow downs.

If you really want a 50Mbps service 100% of the time regardless you pay for an uncontended virtual leased line on fibre - and my goodness will it cost ya!

[JGO]

Thanks for the clarification.

I take it the rule about combining lines because everyone doesn't want them at the same time only applies to 'phones - helps if you are on the night shift ! 

[c6em]

Not really, it applies to many things - I know it under the name of 'diversity'.
This is where the max capacity of the unit is not assumed to be used 100% of the time, or indeed even at 100% capacity at all except for short periods which get treated almost as an acceptable short term overload from a design point of view.
So you can design some aspect of this in mind with a view to making it cheaper....or indeed even making it viable at all in the first place as a commercially 'sellable' product.

Typically examples of this are
Electric Cooker supplies - assumes not every ring/oven/hob/grill are all being used 100% on at full tilt together so the rating of the supply is lower then it needs to be in theory.  Same with kitchen ring circuits.  This is written into the wiring regulations and can be calculated and written up.
Cars - they really are not intended to be used or designed for use at 110mph (or their max speed) 100% of the time....you could say the same thing about roads - useable at full speed until a significant number of others start using them alongside you.

Slightly different but the same sort of principal:
Lots of things rated as 'DIY tools' compared to those rated as "industrial tools".  You use the first category each day every day it will break - unlike the second category which is designed for such use and is generally much more expensive.  The DIY tool is designed for occasional use.
Veering OTT here and taking DIY/vs industrial one stage further -
Jet engines - you can run them cooler at lower ratings and with less maintenance/inspection regimes required (example for ground based power generation driving a generator) or you can run them hotter and give out more power and require more intensive inspections (commercial jet transport) or you can really crank up the power and temperature you let them run at (jet fighters).  This final use requires some unbelievable amount of hours maintenance per flying hour to be done and shortens the life of the engine very considerably.