BT Cabinets - FTTC vs Voice

Guys, I'm just trying to find out how the placement of the FTTC vs Original Cabs works out in practice.

When I did a check for FTTC availability the BT checker came back with a cab number which I'm familiar with and it's the old type cab box around the corner from me that I'm 99% sure I'm served by. However short of a new FTTC type cab hiding behind a bush or behind hoardings (which is possible) there's no obvious FTTC cab in tandem with this old type cab.

Looking on a fairly up-to-date google streetview of my area it seems quite normal to find FTTC and the old type boxes in close proximity of each other which makes perfect sense.

So looking a little further a field in relation to my numbered cab box there's an FTTC box with another old type box around 30-40 metres away. Is it likely or common practice to link FTTC boxes to the old cabs even if they are not in close proximity to them. Or is 30-40 metres considered fairly close still?

Thanks.

Normally within 50m of the PCP, but not always. Are you sure the cab you are looking at is your cab ?

In reply to a post by Zarjaz:

Normally within 50m of the PCP, but not always. Are you sure the cab you are looking at is your cab ?

Yes, I've heard the engineers over the years say it's just around the corner in so and so road, plus the cab is stenciled twice with a number which corresponds to the BT/BTOR Fibre lookup where it quotes the cab number.

This is the BT web address that states the cab number too and where I've obtained my info:-
http://www.dslchecker.bt.com/adsl/ADSLChecker.Teleph...

So here's the cab but the DSLAM is close but not instantly apparent.
It is in the alleyway next to No.15, (Not there when the photo was taken obviously)

In answer to the original question, Openreach has a team of planners ......
The DSLAM position is based on many things, proximity to a usable power supply, permission from local authorities, space and ductwork nearby, etc, etc,

I'll have to see if there is another Fibre cabinet hidden, although you can see where the BT ducting is and where the tarmac has been up and it's as if my old cab is connected to a huawei 288 ( as per cab pictures on Bob's website - RobertoS) some 40 metres away even though the huawei has an old cab like mine a few metres away from it too.

Courtesy of RobertoS.

This is my cab type and it's the same for all around the vicinity:-
http://www.robertos.me.uk/html/bt_furniture_0.html

and this is what the FTTC cab looks like about 40 metres away:-
http://www.robertos.me.uk/html/bt_furniture_2.html

Edited by Vorlon (Wed 08-Jun-16 14:08:27)

What is the number on the other old cab, and are you sure it's a BT one, not VM? Some also on my site. VM cabs have long numbers.

Hang on, are you saying you think that cannot be your cab because of the state of it ? Almost certainly wrong.

If it's within 50m like you say, then it most likely is your fibre cabinet. They don't have to be sat right next to each other. They can be on the opposite side of the road/round the corner, or indeed the next street away. It all depends on local area and what's available in terms of space, underground pipe works, power and sometimes permission, all of which have been mentioned above.

In reply to a post by lee111s:

If it's within 50m like you say, then it most likely is your fibre cabinet. They don't have to be sat right next to each other. They can be on the opposite side of the road/round the corner, or indeed the next street away. It all depends on local area and what's available in terms of space, underground pipe works, power and sometimes permission, all of which have been mentioned above.

I wondered if this could be the case and you've probably answered my question.

Just to clarify - My cab box looks as though it sits on it's own, is numbered in big letters (twice!) as per the BT checker is of the same number and is of the old type - this is definitely my cab (also confirmed by BTOR engineers dealing with previous faults).
So I'm guessing the FTTC cab that also has an old style cab next to it too and is approx 40metres up the road, basically serves my cab aswell.

It makes sense to me that one FTTC cab may serve more than one PCP if they are all within a certain distance whilst still within expected FTTC demand numbers. I have just been used to seeing new FTTC cabinets usually reside next to an established PCP's and assumed (wrongly it would seem) that was the way it was done.

I don't think more than one FTTC cabinet serves more than one voice cabinet.

I don't recall seeing you mention your exchange and cabinet in this thread but has Zarjaz identified the location in his earlier post?

It makes sense to me that one FTTC cab may serve more than one PCP

It may make sense to you but this is not the case. More than one FTTC cabinet can serve one PCP due to high demand but BT do not share FTTC cabinets between PCPs.

Nope. An FTTC cab is only ever connected to a single PCP.

If the FTTC cab you've found is next to a BT PCP with a different number, then the chances are that it has nothing to do with your line or cab.

Where I am sitting right now, there are 3 PCPs within 40m, each with 1 FTTC cab. They aren't always a long way apart.

In almost every deployment, the original PCP (steel, cast iron or fibreglass) stays in place. The (vented) FTTC cab is always a nearby addition.

Was Zarjaz's earlier post not a link to your particular cabinet? With the FTTC cabinet down a side street? Or was he just giving an example of a hidden FTTC cabinet?

but has Zarjaz identified the location in his earlier post?

Dear me, no. They were of a cab in London Street, Reading, was trying to show the OP that the DSLAM's location isn't always so obvious.

In reply to a post by WWWombat:

Nope. An FTTC cab is only ever connected to a single PCP.

If the FTTC cab you've found is next to a BT PCP with a different number, then the chances are that it has nothing to do with your line or cab.

Which is why I asked him for the other old cabinet's number, but he hasn't said. .

In reply to a post by WWWombat:

Nope. An FTTC cab is only ever connected to a single PCP.

If the FTTC cab you've found is next to a BT PCP with a different number, then the chances are that it has nothing to do with your line or cab.

Where I am sitting right now, there are 3 PCPs within 40m, each with 1 FTTC cab. They aren't always a long way apart.

In almost every deployment, the original PCP (steel, cast iron or fibreglass) stays in place. The (vented) FTTC cab is always a nearby addition.

Was Zarjaz's earlier post not a link to your particular cabinet? With the FTTC cabinet down a side street? Or was he just giving an example of a hidden FTTC cabinet?

No, not at all, as Zarjaz points out he gave an example of where an FTTC cab may be hidden around a corner.

All I can do is see if there is an FTTC cabinet hidden in the vicinity serving my PCP directly. I'm surprised that although the nearest visible FTTC cab resides 40 metres down the road with it's own close by PCP, is it not practice for cabling to link two PCP's together?
If so (and within a certain distance ie say less than 50 metres), the FTTC cabinet (down the street) could be indirectly connected to by my PCP by going via it's PCP first? That could be done in theory but is it done in practice?

In reply to a post by RobertoS:

In reply to a post by WWWombat:

Nope. An FTTC cab is only ever connected to a single PCP.

If the FTTC cab you've found is next to a BT PCP with a different number, then the chances are that it has nothing to do with your line or cab.

Which is why I asked him for the other old cabinet's number, but he hasn't said. .

The number isn't visible on the PCP down the street that resides next to the FTTC cabinet.

What you suggest does not happen in practice

Post deleted by Vorlon

Each fibre cabinet will only serve one PCP

In reply to a post by MrSaffron:

Each fibre cabinet will only serve one PCP

Do PCP's ever get linked together or are they Star connected from the exchange?

No, its not practice to wire two PCPs together. However the E-side cable from the exchange to the more distant PCP might well pass through the ducting that goes under/past-ish the closer PCP.

FTTC cabs can be as far away as 100m, but BT really prefer them to be within 50m.

In the deployments I have seen, the cables between PCP and FTTC cabinet tend to have new ducting laid between the FTTC cabinet and the footway chamber just in front of the PCP. I suspect that BT would prefer not to put the tie cables into existing ducts, but there are plenty of cabs that I haven't seen ... so this impression might be wrong.

Do PCP's ever get linked together or are they Star connected from the exchange?

Sometimes a circuit might have two PCP's in its routing.

'Star connected' doesn't quite cover it, more akin to tree branches.

Nope. Or was he just giving an example of a hidden FTTC cabinet?

The number isn't visible on the PCP down the street that resides next to the FTTC cabinet.

What cab number off of which exchange does the checker you linked to earlier say you are connected too ?

Tell the forum, and someone on here will kindly look it up for you.

I think we need to think about how cables get added over time, too.

In the fifties, a 1000-pair cable might have run out of the exchange, and fed into a tree of a few PCPs. A decade later, capacity might have been running low, and a 500-pair cable needs to be added, with a couple of hundred extra pairs run into two or three of the PCPs.

What I've seen of a snapshot of E-side records nowadays suggests that the feed into a PCP has grown over time, with a couple of hundred pairs taken out of one (larger) E-side cable, plus a couple of hundred out of another, plus a hundred out of a third. With the remainder of the E-sides continuing onwards.

Then add on the complication that each of these groupings is made of different lengths of 0.32mm copper, 0.4mm copper and 0.5mm copper.

In reply to a post by Zarjaz:

The number isn't visible on the PCP down the street that resides next to the FTTC cabinet.

What cab number off of which exchange does the checker you linked to earlier say you are connected too ?

Tell the forum, and someone on here will kindly look it up for you.

I'm on the THAD exchange and the cab number given by the various checkers is 76 and I know that to be the PCP that BTOR have worked on in regards to my line in the past.

I'm on the THAD exchange and the cab number given by the various checkers is 76

Aha, so it's in Thameswey district somewhere, though not an exchange code I'm familiar with.

In reply to a post by Zarjaz:

I'm on the THAD exchange and the cab number given by the various checkers is 76

Aha, so it's in Thameswey district somewhere, though not an exchange code I'm familiar with.

I'm not familiar with that district either - this is in hampshire.

Cab 76 in Aldershot.

Since the PCP only has 170 odd lines, you are going to be looking for a small DSAM - unlikely to be the one outside the job centre assuming the PCP next to that is active

How old are the pictures on Google Maps? - https://www.google.co.uk/maps/place/14C+Arthur+St,+A...

Edited by gt94sss2 (Wed 08-Jun-16 23:04:54)

THAD and the TH means its part of the district BT calls Thamesway - not that it is in a place called Thamesway

https://www.google.co.uk/maps/@51.2474409,-0.7605007...

Believe this is the fibre cabinet that serves PCP 76 on THAD exchange

Based on pavement tarmac I believe cab 76 is served by the fibre cab I linked to, and the beaten up green cab might be a Virgin Media one (hard to tell with the graffiti/posters)

In reply to a post by gt94sss2:

Cab 76 in Aldershot.

Since the PCP only has 170 odd lines, you are going to be looking for a small DSAM - unlikely to be the one outside the job centre assuming the PCP next to that is active

How old are the pictures on Google Maps? - https://www.google.co.uk/maps/place/14C+Arthur+St,+A...

That's the link I gave Bob. If you look top left of the google page it says nov15 when images taken.

In reply to a post by MrSaffron:

THAD and the TH means its part of the district BT calls Thamesway - not that it is in a place called Thamesway

https://www.google.co.uk/maps/@51.2474409,-0.7605007...

Believe this is the fibre cabinet that serves PCP 76 on THAD exchange

Ah, that makes sense then so my PCP which is further down the road is linked to this Fibre cab. As you say the grafitti makes it hard to know what the accompanying PCP esq cabinet has written on it.

VM cabs usually have their numbers on an endplate, not the front like the BT ones.

However the double manhole cover looks to me like BT. I can't see what the letters in the middle of the covers are. If so I very much doubt if it's a VM one.

I think it is a Virgin Media cabinet, there are no other BT cabinets that I expect to see in that road.

After all that, I know Aldershot well, my Mum lives in Cargate Ave, and I have worked Aldershot patch quite a fair bit over the years. Just didn't recognise the short code.

In reply to a post by Zarjaz:

After all that, I know Aldershot well, my Mum lives in Cargate Ave, and I have worked Aldershot patch quite a fair bit over the years. Just didn't recognise the short code.

Small World

Thanks for all the feedback guys, it's much appreciated - I will double check today to see if BT haven't sneaked any FTTC Cabinet into the vicinity or if for some strange reason I've been blind to it.

Edited by Vorlon (Thu 09-Jun-16 10:32:50)

On a tecnical note - a question.

When a home has a FTTC active connection and an active landline do the voice signals take the route back via the fibre too (after the copper bit) or do they take their original route back via the PCP's and copper lines to the exchange?

Voice will head back to the telephone exchange as normal for now (a product where this does not happen is on the way).

Having looked at the area, there is no reason for another fibre cab to be in that area other than to serve cabinet 76, and if you trace the tarmac you can see power feed and also copper link to existing cabinet.

A standard PSTN voice connection continues to take the copper route. Just diverted through the FTTC one to pick up or drop the VDSL2 signal. This is exactly how voice and ADSLx works in the exchange. See also the FTTC page on my website.

The only times this isn't the case is when VOIP is used by the subscriber. This can be taken with or without a PSTN service, using different numbers, if supported by the ISP.

It is normally possible to port a PSTN number to VOIP, with or without retaining a PSTN connection. They still need different numbers.

Whether it is technically possible to run PSTN and VOIP with the same number I don't know. I doubt it, which is why I said above they have to be different. They normally are.

Just a bit of extra info.

The cab that Andrew thought could be Virgin Media or I suppose NTL (as it used to be around here) has no markings or plates at all. The manhole covers in front of it though have "CATV" marked on them. The other thing to note about this possible virgin cable cab is that unlike my BT PCP which has two securing points on the doors this has only one centerally mounted.

There were no other FTTC cabinets in the vicinity of my PCP either, so Andrew must be right.

From google/Wikipedia:

CATV (originally "community antenna television," now often "community access television") is more commonly known as "cable TV."

In reply to a post by ian72:

From google/Wikipedia:

CATV (originally "community antenna television," now often "community access television") is more commonly known as "cable TV."

Thanks Ian72, so that sort of indicates what has been suggested.

At least I can say with some confidence now that the FTTC cabinet which is a distance away from my PCP approx 30 - 40metres appears to be the correct pairing.

Yes, as has been confirmed, the CATV manhole chamber covers are VM or one of its predecessors that it bought.

What is the maximum number of PSTN lines through a PCP?

A lot. But it obviously depends on what size it is in the first place.

The PCP (one of the large ones) that serves my new place covers around 1100 addresses and that includes 80 houses on the new estate I'm moving to. The also two new developments, one starting this year and the other next year, which will be covered by the same cab and add another 240 addresses.