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Author Topic: How exactly is BT Infinity connected up?  (Read 9474 times)

HPsauce

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How exactly is BT Infinity connected up?
« on: March 01, 2011, 07:04:07 PM »

A question on another forum made me wonder about this, and the exact technology used.
I didn't see any details on Kitz main site, so maybe one of the BT experts can explain?   :graduate:

From what little I know, new (powered) cabinets are installed "fairly close" to the existing phone cabinets, presumably linked somehow (but how?).
Presumably these terminate the fibre from the exchange and then provide a local "broadband" type of signal.
But how are they then tied in to the phone EXACTLY and delivered to your house?
For example is it a separate cable (seems unlikely) or some sort of multiplexing (presumably) - proprietary or like ADSL alongside voice?

And does the voice then use the fibre, or does the old copper line to the exchange remain?
Whichever is used, how is the cable to your house tied in to both services?

And what happens when you decide to give up on the system and revert to a "standard" phone line and enable ADSL?

A good explanation would definitely warrant a "sticky".  ;D
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razpag

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Re: How exactly is BT Infinity connected up?
« Reply #1 on: March 01, 2011, 07:21:18 PM »

Can't be bothered giving an in-depth explanation, suffice to say that yes, the new Fibre Cabs are to be installed within 100mtrs of the original Cabs.

The connection method is exactly the same as with ADSL, it's just the DSLAM is now in the Fibre Cab. So, the PSTN will be on the E-side in the old Cab, this will then be connected to a link cable that goes to the new Cab which is pre-connected to the DSLAM.
The return leg is also pre-connected in the new Cab to a link cable going back to the old Cab. So, the Dial tone and the Broadband signal now both appear in the old Cab and just require wiring up to the D-side going on to the EU's premises.

Hard to explain really, but in simple terme the engineer just needs to work in the old Cab as all the work in the new Cab is pre-connected to the link cables.

Reminds me of similar introductions to an old series calles 'SOAP' for those over 40 yrs of age. ;D 
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HPsauce

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Re: How exactly is BT Infinity connected up?
« Reply #2 on: March 01, 2011, 11:00:24 PM »

OK, thanks, that makes sense.
So the old copper from the exchange to the old cabinet is still used for dial tone.
It's then diverted off to the new cabinet and back in a sort of loop, picking up the broadband on the way.
(same as in the exchange for some LLU, like Bethere for example)

Must be a bit crowded in the old cabinet!  ???

Is there some sort of power-fail mode so that your phone keeps working if the FTTC loses power?
(I guess there must be to comply with emergency call requirements)
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waltergmw

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Re: How exactly is BT Infinity connected up?
« Reply #3 on: March 02, 2011, 12:14:18 AM »

@ HP,

RazPag has described the Infinity solution you asked about which uses the Shared Metallic Path Facility so you use two pairs in the inter-cabinet link cable.
Some others use the Full Metallic Path Facility so their phone service is done over VOIP. It still has an emergency capability as that is a statutory requirement.
The FMPF uses a single pair in the link cable so you have no connection back to the exchange. All FTTC cabinets have a UPS system with reasonably large batteries and you are instructed to have your own tiny UPS to power your house modem in the event of an outage. The PCP remains a Passive device with no power in it.

Here's some pictures
The "Krone blocks" (IDC connector blocks) which terminate the link cable(s) are hidden to the right end of the cabinet.
The two fat grey cables take the lines into the MSAN.
Power on right, VOIP above MSAN at the top
Dark Grey unit at the bottom is BT's Fibre router.
HVAC unit to the left
"Meeting" pit contains both Fibre and link cable to PCP 1 on the right of the picture.

http://www.relay-rutlandtelecom.co.uk/images/lyddington/launch/P1080368.JPG
http://www.relay-rutlandtelecom.co.uk/images/lyddington/launch/P1080357.JPG

Kind regards,
Walter
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HPsauce

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Re: How exactly is BT Infinity connected up?
« Reply #4 on: March 02, 2011, 09:10:17 AM »

Some others use the Full Metallic Path Facility so their phone service is done over VOIP.
Sorry, can you clarify what you mean by "some others" please?
Obviously I was asking about BT Infinity specifically, do you mean the likes of PlusNet who are providing (trialling?) FTTC services using BT kit, or do you mean specialist companies who provide all the equipment themselves, or for that matter Virgin cable?

I'm interested in all that too, but would like to keep this particular thread on just the BT Infinity implementation please, and all the ISP's who use it.  ;)
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waltergmw

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Re: How exactly is BT Infinity connected up?
« Reply #5 on: March 02, 2011, 10:14:45 AM »

@HP,

I will attempt to comment on your particular subject as it is quite plain that the pictures are not of the Infinity product and that there are a few others installing their own versions of FTTC.

One of the most important questions must surely be is how a CP having invested quite substantially in Exchange based LLU ( which is now being out-performed, except for direct exchange connections) can continue with adequate ROI on that equipment and, in parallel, either add new clients into an Infinity arrangement at BT's wholesale prices or even migrate some of their LLU services back to an Infinity arrangement, presumably attracting the 127 twisted pair charge as well as a new VDSL modem cost ? In this situation it is not impossible that a CP might decide, as I believe Orange have already done, that they are not able to continue with their individual offerings.

Perhaps it may also dawn on consumers that any Infinity scheme can be no match for a Virgin Fibre-coax product IF that service is available to them. The only differentiators then are price, capacity of service and possibly the quality of support.

Kind regards,
Walter
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HPsauce

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Re: How exactly is BT Infinity connected up?
« Reply #6 on: March 02, 2011, 10:41:22 AM »

One of the most important questions must surely be is how a CP having invested quite substantially in Exchange based LLU ( which is now being out-performed, except for direct exchange connections) can continue with adequate ROI on that equipment and, in parallel, either add new clients into an Infinity arrangement at BT's wholesale prices or even migrate some of their LLU services back to an Infinity arrangement,
Indeed, as a Bethere customer myself that is of considerable interest.

Though in my case it's more about the future of the company as personally I do have Virgin cable available and there's no likelihood of BT installing their FTTC in our area in the foreseeable future.

Having suffered badly from BT's DLM and throttling (aka "traffic management") with various ISP's in the past I'm very wary of moving back into the clutches of BT or their systems.  :'(
(and Virgin is equally unattractive)

Also:
presumably attracting the 127 twisted pair charge
I don't know what that is, can you explain please. e.g. what's it for and is it a one-off or recurring?
« Last Edit: March 02, 2011, 10:45:36 AM by HPsauce »
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waltergmw

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Re: How exactly is BT Infinity connected up?
« Reply #7 on: March 02, 2011, 01:09:35 PM »

Hi HP,

I'm referring to the SLU price schedule (dated 21/04/10) non BT CP's have to pay BT O.
(Perhaps these charges need to be compared with the 50 connection fee that BT charge a new FTTC consumer.)

These are installation charges:-
100 pr tie cable 765.32 + annual rental of 42.14
Sub loop connection charge (For EVERY twisted pair, whether batched or not) 127.61 + either FMPF rental of 93.96 or SMPF rental of 11.47
Further charges for duct work are also required.
PCP Extension upgrade** 1829.11


**3) Charges for Sub-Loop PCP Extension Works will apply whenever a Full Survey identifies
existing space is exhausted. The price will cover the replacement of the cabinet fabric only.
Additional work, if required to facilitate the fabric change or to enable the installation of Sub
Loop tie cables will be charged on a bespoke basis.

N.B. these are only extracts and I have no information as to whether these prices have been revised.

Kind regards,
Walter
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HPsauce

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Re: How exactly is BT Infinity connected up?
« Reply #8 on: March 02, 2011, 01:23:09 PM »

Presumably BT retail have to pay these charges too, so factor them in to their minimum period (18 months?) and associated startup and ongoing charges on FTTC contracts?
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waltergmw

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Re: How exactly is BT Infinity connected up?
« Reply #9 on: March 02, 2011, 02:09:49 PM »

Yes Minister, but I couldn't possibly comment !
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razpag

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Re: How exactly is BT Infinity connected up?
« Reply #10 on: March 02, 2011, 04:11:06 PM »

Scandalous !! You'd think they were running a business !!  ;)
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