Kitz Forum
Broadband Related => ADSL Issues => Topic started by: Weaver on December 13, 2015, 06:57:07 PM
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As many if you will know, I have three lines which are over "63.5" dB d/s attenuation. I think my line is 4.6 miles long (7400 m) on the assumption that it follows the road which seems to be the only practicable route. Given that 63.5 dB is the reporting limit in some protocol within the DSL system, in that case, any ideas about what the true attenuation figure might be?
Apologies if I've posted on this topic before, I forget.
I've tried various tools, but most of them simply say that 4.6 miles is off the scale or won't handle values higher than 63.5 dB.
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I seem to remember that the old 2-Wire 2700HGV used to report the actual attenuation even if over 63.5 dB.
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I've seen people reporting higher figures from Netgear kit for example. For what it's worth we show 57dB for 5.3km so if you scale that up to your line length you'd get something like 76dB. However it won't be linear as the higher frequencies will drop out quicker, so you presumably won't be using them.
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@roseway - thank you I had forgotten that.
@AESmith - I was wondering about a tool that could do extrapolation to longer lengths correctly beyond 63.5 dB, taking into account the effects you mentioned.
Why do tools and graphs published simply give up, believe that service over such line lengths is impossible? Is it perhaps the case that service would normally be impossible without a very, very good metallic path, one that's unusually good? Some of my neighbours have much more difficult conditions, on lengths 1 km longer, getting sub 1 Mb/s service.
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@everyone - If you have a line with such an attenuation or similar length or worse, would you post something telling me/us all about it?
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By the way, I should have asked him where it originated but the OR guy who did the SFI visit has a graph on screen with speeds vs distance, and he was coming up with around 4meg at 5 km, pretty similar to what we actually get. I'm sure 5km wasn't the end of his range, but I can't say I noticed whether it went up to your 7+ km.
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It's not the distance so much, as the actual attenuation, as I'm sure we're all aware. Unless the cable size (poundage) is known, then it really is pure guess-work ??
I tend to use 13dB attenuation per Km, as an approximate guide for 0.5 Cu cable. I have no converters or tables to tell me what that same Km's attenuation would be, if it was run in 0.9 Cu, or conversely 0.4 Al ?? As there is a damn site more 0.5 Cu than Al in the D-side network, then I would just use the 13dB guide. :)
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@BlackSheep - woah :- 7.4 × 13 = 96.2 dB ! Sounds like I'm in trouble if I'm on 96dB d/s attn.
It shows you how inadequate a lot of the tables graphs and tools are if they pack up somewhere around the 63.5 dB - 75 dB point.
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Ha ha ...... believe me, you won' have an attenuation of 96dB and be receiving DSL over fixed-line cables. ;) ;D.
This is why it is paramount to know the exact distances involved combined with the exact make-up of the cable. Long D-side line lengths have often been made up of a hybrid of higher poundage cables, such as 0.63 Cu and 0.9 Cu, which would bring your attenuation right down to a, 'within range' integer.
Ezzer (an ex-BT engineer with a wealth of knowledge), along with other educated members of the forums had a mini-discussion here ... http://forum.kitz.co.uk/index.php?topic=1448.0 .... about something similar. You will notice he had a line in-synch at 9.6Km (I think he said ?), but this was fed over mainly 0.63mm Cu cable.
My own personal experience has seen me attaining synch (ADSL) on an 86dB cable-run, albeit only at around the 0.3meg mark. Spent days wih another engineer, clearing umpteen battery contact faults in wet buried joints up a very big hill, in order to get a 'Line Test OK'. Knowing full well, that even when we had achieved this LTOK result, the circuit would struggle like hell to synch. But them's the rules, the ISP's require a LTOK and quite rightly so. :)
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Well the 4.6 mi figure is accurate presuming that the cable follows the road, the only other option is for it to go over the moor. The road route is just due north then due west, two roads and you're at the exchange. You can see the cable by the side of the road on the northbound section.
So that leaves the 13 dB figure?
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Does your ISP have a figure for your line length? In among the figures that Pxxxxxx paste into my fault ticket, there's often a couple of length figures which my case are ..
Line Length (DN) 5300
Line Length (DP) 5300
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4.6 miles = (4.6 x 8) / 5 km = 7.36 km
Are you able to harvest the Hlog data for one of your lines? If so, I would appreciate a copy of the raw data (that is the list of the individual attenuations (in dBm) per 4.3125 kHz wide tone).
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> Are you able to harvest the Hlog data for one of your lines?
Beyond my physical abilities, I'm afraid. (As explained earlier, you'll recall.)
It's not one of the parameters that A & A's "clueless" server harvests when it extracts info from modems remotely (somehow) to prepare me a report. It pulls out sync rates error counts hec errors, errored seconds - the usual stuff.
(I'm assuming that it would require telnet access into the modem ?)
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A perfect job for a raspberry pi - excuse for buying one needed - except that it would need more Ethernet ports on it.
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I used https://www.freemaptools.com/measure-distance.htm
And 1 mi = (1760 × 3 × 12 × 0.0254) m :: exactly
= 1609.344 m
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It's not one of the parameters that A & A's "clueless" server harvests when it extracts info from modems remotely (somehow) to prepare me a report. It pulls out sync rates error counts hec errors, errored seconds - the usual stuff.
Off topic, but do they truly collect from the modem, which would imply it needs to be one that supports their choice of management protocol, or do they get it from the DSLAM? "P
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@aesmith - my feeling is that perhaps I should say it's from the DSLAM, I just don't know.
I don't know whether one of the TR-xx protocols has this kind of errors and stats extraction capability, to suck data out of the modem.
A & A sometimes have entries in their database for what kind of modem or router the user has (can be wrong, out of data) but I don't know to what extent they employ TR-xx.
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@BlackSheep -
> Long D-side line lengths have often been made up of a hybrid of higher poundage cables, such as 0.63 Cu and 0.9 Cu, which would bring your attenuation right down to a, 'within range' integer. [my emphasis]
* Is that your feeling then? High poundage done specially for me? Good local BTOR boys!
(I am assuming, forgive my ignorance, that poundage = good cross-sectional area = good kg m-1 )
> right down to a, 'within range' integer
Would that be something in the sixties, or seventies, or what? Given that I d/s sync at 2100 - 2400 on a good day.
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@BlackSheep -
> Long D-side line lengths have often been made up of a hybrid of higher poundage cables, such as 0.63 Cu and 0.9 Cu, which would bring your attenuation right down to a, 'within range' integer. [my emphasis]
* Is that your feeling then? High poundage done specially for me? Good local BTOR boys!
(I am assuming, forgive my ignorance, that poundage = good cross-sectional area = good kg m-1 )
> right down to a, 'within range' integer
Would that be something in the sixties, or seventies, or what? Given that I d/s sync at 2100 - 2400 on a good day.
Absolutely correct re: poundage of the cable. I can only ever guess (unless you PM me your landline number - or DP and Exchange Name) what cable poundages are used. But I know on my semi-rural / semi-urban patch, that longer D-side runs would sometimes have sections of higher than average poundage cables put in the ground.
Definitely not in the 70's with a 2+Meg speed. :)
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Would that be something in the sixties, or seventies, or what? Given that I d/s sync at 2100 - 2400 on a good day.
Not having a low-flying raven within reach (to disembowel and to scatter the entrails in an aid to divination), I would guess that your true attenuation will be in the 65 - 68 dB range. (But I could be wrong.)
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@BlackSheep - one of the three lines is 01471xxxxxx
[Moderator edited to obscure the above number.]
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@Burakkucat, @BlackSheep - thank you for your continued kindness, patience and wisdom in the face of so very many dopey questions. You have however helped me understand a lot.
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FYI, One of my neighbours, a couple of hundred metres or so further from civilisation than me, can sync at >2300.
I am the closest house to civilisation, northernmost, on the edge of the village of Heasta.
In fact, I did my neighbour's DSL installation, many, many years ago, so I was trying to use the best of everything, SSFP, the best cabling and a Netgear DG384 just as I was using myself (eating your own dogfood).
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I wonder if it is possible that they did some serious upgrade work around the time (2004) when ADSL was first made available.
Does / did this kind of thing happen - “poundage” upgrades, in advance of DSL on ridiculously long lines?
I remember that before that some repairs were carried out on the moor but I have no clue as to the extent of them. Crackles on the line from time to time were rapidly fixed. A very bad section of cable lying on the ground was a continuous problem as vehicles constantly were driving over it in order to get to the local fank, which necessitated its burying in order to protect it from more and more damage to the insulation. At the time I was using a dialup modem which regularly managed to get 48 kbps and was extremely reliable, so the line was very clean even back then, free of his and clear on the higher audio frequencies at any rate.
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@BlackSheep - one of the three lines is 01471xxxxxx
Got the relevant info to work on later. I'd personally have your number deleted by one of the Mods, or re-edit the post now, Weaver. Get back to you later, my friend. :)
[Moderator edited to obscure the telephone number in the above quotation.]
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FYI, One of my neighbours, a couple of hundred metres or so further from civilisation than me, can sync at >2300.
I am the closest house to civilisation, northernmost, on the edge of the village of Heasta.
In fact, I did my neighbour's DSL installation, many, many years ago, so I was trying to use the best of everything, SSFP, the best cabling and a Netgear DG384 just as I was using myself (eating your own dogfood).
The circuit number you gave me is also synching around that rate. :)
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I wonder if it is possible that they did some serious upgrade work around the time (2004) when ADSL was first made available.
Does / did this kind of thing happen - “poundage” upgrades, in advance of DSL on ridiculously long lines?
I remember that before that some repairs were carried out on the moor but I have no clue as to the extent of them. Crackles on the line from time to time were rapidly fixed. A very bad section of cable lying on the ground was a continuous problem as vehicles constantly were driving over it in order to get to the local fank, which necessitated its burying in order to protect it from more and more damage to the insulation. At the time I was using a dialup modem which regularly managed to get 48 kbps and was extremely reliable, so the line was very clean even back then, free of his and clear on the higher audio frequencies at any rate.
'Poundage upgrades' are really decisions made by the Planners. Broadband has always been touted as a 'Best efforts' product due o the various types and sizes of legacy cable in the network.
I would very much doubt anything in excess of 50-100mtrs of higher poundage cable would be 'upgraded', due to this policy and of course the cost.
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Interestingly, when that telephone number was put into the BT Broadband Availability Checker (http://www.dslchecker.bt.com/adsl/adslchecker.welcome) it indicated that WBC ADSL2+ is available.
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Hi Weaver ...... I've looked at the cable run and you are quite right in that it almost follows the course of the road all he way back to the Exchange. There's the odd deviation but nothing to shout about.
The good news for you and your neighbours, is that way back when, the GPO laid the majority of the underground cable in varying lengths of 0.6 and 0.9 Cu. This thicker poundage cable runs from your DP all the way back to a cable-joint, somewhere around the entrance to the covered reservoir / Water Treatment Works. This WTW is on your left as you drive back to Broadford, approx. 5.5Km from the DP.
The rest of the run is 0.5Cu from the cable-joint to the Exchange.
:)
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@BlackSheep @Burakkucat - many many thanks for your kindness
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I suppose that back then in 2004 if we had not been fortunate to have had the really good thick Cu that we did have, then we would have had no possibility of any DSL service at all, not even the 0.5 Mbps fixed rate that we were getting back at first.
Perhaps it just shows you how much can be achieved using really good quality Cu.
Anyway, I suspect the answer to my original question of this thread might be ~ 65 - 68dB or thereabouts but not massively higher.
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With the little snippets of information that has appeared in this thread and with the help of Google Maps, I now understand the "lay of the land".
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I am at the very northernmost end of the light green-coloured area, the post code is at number six half way down the bank to the sea.
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Btw with the exception of the water board place, between home and the houses near the main road, there is not a single house, nor tree, nor wall, nor any sign of human habitation along the entire run of the line. Presumably this lack of civilisation has to be pretty helpful, as there is no mains near the cable, nor any local source of EM interference, all there is is the ever pervasive more distant AM radio sources.
The cable bundle is lying in water in some places, lying on top of the heather or rocks for a good proportion of the run. It has been buried in some places certainly where needed.
When it gets near to my house, it is on the far side of the road, my three lines depart from those for the rest of the village. My lines ascend a tall wooden pole to gain enough height to cross the road and from there crosses the road while climbing still to a second pole on my side which is much, much higher as my house stands way above the road.
The very last part of the run from the last pole is horizontal at first floor height and radial, and the three lines come straight into the office to the SSFPs by the window with the modems adjacent to them.
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Generic info only, I'm afraid.
I understand that thinner copper (or lower poundage) can be seen coming out of exchange buildings, when space in the cable chamber or exchange manhole is at a premium. It can (and I guess often is) jointed to thicker stuff as it spreads out - so it isn't a surprise to see it go beyond the standard 0.5mm for the longest, most rural lines.
As this thread shows, some lines are *way* longer than 5km. However, in terms of "electrical length" (aka attenuation), BT says that no lines are longer than 6.5km of 0.5mm copper. Anything that is actually physically longer than this must have some fatter copper in there.
Source: Sagentia, 2008 (pages 3-6).
http://stakeholders.ofcom.org.uk/binaries/research/technology-research/asses.pdf
I recently read something that reckoned the first 1km of copper out of a KC exchange in Hull was 0.3mm.
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I wonder what the record longest and worst Kitizen's link is (ever)?
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Generic info only, I'm afraid.
I understand that thinner copper (or lower poundage) can be seen coming out of exchange buildings, when space in the cable chamber or exchange manhole is at a premium. It can (and I guess often is) jointed to thicker stuff as it spreads out - so it isn't a surprise to see it go beyond the standard 0.5mm for the longest, most rural lines.
As this thread shows, some lines are *way* longer than 5km. However, in terms of "electrical length" (aka attenuation), BT says that no lines are longer than 6.5km of 0.5mm copper. Anything that is actually physically longer than this must have some fatter copper in there.
Source: Sagentia, 2008 (pages 3-6).
http://stakeholders.ofcom.org.uk/binaries/research/technology-research/asses.pdf
I recently read something that reckoned the first 1km of copper out of a KC exchange in Hull was 0.3mm.
0.32mm cable is also a common'ish cable used on E-side runs. Most E-side runs are made up of varying lengths of Cu/Al and utilising the various poundage's available.
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Found the time to capture a 'Scheme Plan' for one of our Cabs. I've erased a few details but the ones that are left show that this particular Cab is fed via 3 cables from the Exchange, giving a breakdown of what the total cable length is made up from ..... ie: CU or Al, length of that section, and poundage size.
You'll see 0.32mm appears.
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Interesting. So three cables, a 200 pair, a 100 pair and a 50 pair.
I am assuming that the third (50 pair) cable has been described "back to front"? I.e. 0.5 Cu, then 0.4 Cu and finally 0.32 Cu. :-\
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Very interesting.
I'd read that the thinner gauge cables are used closer to the exchange, to reduce congestion in the chambers into the exchange building - and when you see some of the photos, you understand why!
http://www.britishtelephones.com/gpo/jointbox2.htm
http://www.britishtelephones.com/gpo/cablechamber.htm
Do those 3 entries represent just the E-side - i.e. the cables on the way towards the PCP? It is interesting to see the total lengths differ by 250m!
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Do those 3 entries represent just the E-side - i.e. the cables on the way towards the PCP?
That is how I have read B*Sheep's words. :)
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To try and clarify further ..........
The E-side 'Pairs' (Pair of wires) to the Cabs, will be 'Dropped off' from various 4800pr cables. The example I give below sees the total number of 'Pairs' within the Cab being made up from 3 separate cables that leave the Exchange MDF.
Looking at the table, the top one has a total of 200prs allocated from one particular Exchange cable. The second in the list has a total of 100prs allocated from another Exchange cable, and the third one in the list has a total of 50prs allocated ..... from yet another different Exchange cable. 350prs in total.
I have to admit, I'm not 100% sure how the breakdown-order runs, whether it's MDF to Cab or Cab to MDF I do not know. Only our 'Second Stage Repair' and 'Pressure' engineers work on E-side cables. Of which I am neither. If we have a faulty E-side pair, we simply swap-out to a spare pair if available. If none are available, then we pass the task to SSR to resolve.
The only other point-of-note that may be of interest, is the attenuation figures in the right-hand columns. These were taken roughly about the same time Moses was receiving the Commandments, and were determined using a 1.6Khz frequency. From this particular table, we can see that the middle cable would be best to carry DSL signals. We do have an application (SEAM), that gives us the equivalent attenuation readings for a 300Khz signal.
Hope this helps, if not .... ask away and if I can help I will. :)
Numbers re-edited, to reflect B*Cats astute observations of my original musings.
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b*cat raises a paw to ask how you read the size (total number of pairs) contained within each of those three cables of your example, above, please?
For the first cable, I see "Pair No. 151-350". I interpret that as 200 pairs.
For the second cable, I see "Pair No. 1-100". I interpret that as 100 pairs.
For the third cable, I see "Pair No. 451-500". I interpret that as 50 pairs.
Slightly puzzled. ???
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Ha ha ........ ye gods ...... my vanity has finally let me down for the last time. I genuinely thought the 'Pair count' was ......................... 151-300 ................ and the 451-500 I read as AS1-500. The letters indicate the 'vertical bar' on the MDF where the circuits are located (Starts A,B,C,D etc etc ........ then AA, AB, AC etc etc ......).
I'm genuinely shocked how poorly I read those numbers !! Pair of bins now welded to my napper !! :blush:
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Having had his evening meal delayed by examining Google Street View, b*cat believes that he has possibly found Weaver-Land. :)
Starting on the A87 to the east of Broadford, I took a long and winding road that was signposted as a "no through road" leading to Heaste / Heasta, five miles distant. Travelling down that road (and taking in the views) I finally crossed a cattle grid and on the left hand side of the road was a sign proclaiming Heasta. (Image below.) Just past that sign is a telephone pole and a cable can be seen leaving that pole, crossing the road to a carrier pole higher up the bank to the left of the big tree. There appears to be another carrier pole to the right of the big tree and then a house.
I shall just say it is a really stunning location as I now depart to eat my evening meal . . . :D
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Don't want to intrude on this erudite conversation, but trying to understand at least something. I found this (http://www.johnhearfield.com/Telephone/Cable.htm) while browsing. Perhaps it may contribute? :-\
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I found this (http://www.johnhearfield.com/Telephone/Cable.htm) while browsing. Perhaps it may contribute? :-\
Looks interesting, thank you.
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@renluop - now that is really useful, thanks very much
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@burakkucat - the wonders of Google street view. Good man!
You've found the correct telephone poles, at road level and house level! In the pic, you see, as you said, a really enormous tree. My house is high up, to the right of that big tree as viewed from the cattle grid where the pic was taken from. From the high level telephone pole, there is a fairly short horizontal run for the three lines into the house at first-floor level into the window of my office (that I used when I was well).
So in fact because you are (relatively) so low down, my house is off to the right above the frame of that shot.
To get a better view, you can walk ahead to the point where the road falls then rises substantially, you can see the house well if you spin round 160° to your right.
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Instructions followed (as best as Google Street View would allow) and another glimpse was obtained between the trees . . .
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You must have wrist-ache after that long, exhausting walk from Broadford.
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I've discovered exactly where the Broadford (NSBFD) Telephone Exchange is. Looking at the Big Church in the centre of Broadford, near the Petrol Station, on the left next door to to the church is a fairly small public toilets building with a brown wooden door. To the left of that is -
- a mysterious building with a traditional tiled roof, no windows, and no obvious door at the front. It's set back a little way so that there's off-street parking for your big Openreach van. It is hopefully a small fortress, a happy home for all those EO lines >:(
Psychic camouflage, the number of times I must have walked past it without noticing this true hub of tech that powers my very life.
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Looking in my 1977 editions of the List of Exchanges (Part 1 -- the red book & Part 2 -- the green book), they tell me that, back then, Broadford was a Unit Automatic Exchange type 13, with facilities for subscribers to use the 999 service and dial their own STD calls. It served 55 businesses and 185 residences. Its parent exchange, from whence all operator services were provided, was Kyle and that was described as a non-Director crossbar exchange type 1 with an auto-manual board. There were 70 businesses and 134 residences served by the latter exchange and it had facilities for subscribers to use the 999 service and dial their own STD calls.
Both Broadford and Kyle were listed as part of the Aberdeen & North of Scotland Telephone Area, Scottish Board.
I suspect that nowadays the Broadford and Kyle exchanges are just remote concentrators for some far-away System X exchange. Maybe Aberdeen? :-\
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I've discovered exactly where the Broadford (NSBFD) Telephone Exchange is. Looking at the Big Church in the centre of Broadford, near the Petrol Station, on the left next door to to the church is a fairly small public toilets building with a brown wooden door. To the left of that is -
- a mysterious building with a traditional tiled roof, no windows, and no obvious door at the front. It's set back a little way so that there's off-street parking for your big Openreach van.
It is a traditional style of building for what was a UAX13, with ventilation louvres for the diesel engined emergency power generating set and a side window & door. I suspect that the power generating set has long been removed and what few equipment racks that now exist each have their own trickle-charged batteries. (No longer a big central battery set.)
Looking closely from either side, we can see that a flat-roofed extension has been built behind the original building. I would guess that there is more empty space than equipment contained within!
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Another very basic question.
Where do the copper paths and any fibre cables physically go to get into / out of the NSBFD exchange? * Really basic stuff like what is buried where? * What is fibre and want is Cu?
* I presume there are some EO lines? * I'm wondering what happened to cables immediately exiting the exchange that are heading for a cab?
* Where does the fibre optical cable go (physically) that plays the main role of backhaul ?
Just trying to get a physical picture of where things are what fibre vs what is metallic path and where things are buried ducted etc? How does BT gain access to the conductors and optics in Broadford?
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Another very basic question.
Where do the copper paths and any fibre cables physically go to get into / out of the NSBFD exchange? * Really basic stuff like what is buried where? * What is fibre and want is Cu?
* I presume there are some EO lines? * I'm wondering what happened to cables immediately exiting the exchange that are heading for a cab?
* Where does the fibre optical cable go (physically) that plays the main role of backhaul ?
Just trying to get a physical picture of where things are what fibre vs what is metallic path and where things are buried ducted etc? How does BT gain access to the conductors and optics in Broadford?
All MPF's (Copper/Ali) are presented on a MDF (Main Distribution Frame). Basically an ironwork frame with labelled blocks to identify the circuit we are working on.
The fibre cables go to a separate part of the building and are presented in lockable cabinets for their engineers to access.
Bothe sets of cables leave all Exchanges the same way ...... through a below ground cable chamber, through the external Exchange man-hole, and then on their way to whatever destination has been planned for them. In urban environment, this will be by ducts with man-holes/joint-boxes at various stages where a mechanical cable joint is required.
In rural environments, and a lot of 1960'70's housing schemes, the cable will be DIG (Direct-In-Ground).
Where do fibre optic cables go ? That's too open-ended to answer, I'm afraid ?? Years ago around my area, they would put various fibre 'Loops' in so that if anyone (normally businesses) wanted fibre BB, they simply tapped into the 'Loop' at the nearest point to the EU.
But I suppose it depends on how near to the Exchange the EU is, the fibre could leave the Exchange and go direct to the premises ?? There's also the fibres that make up the FTTC project.
Both Fibre and MPF go through the same man-holes/joint boxes ............ the fibre cable however will be blown in through a separately installed sub-duct (Basically, a duct within a duct).
Hope this helps in some small way ??
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I've discovered exactly where the Broadford (NSBFD) Telephone Exchange is. Looking at the Big Church in the centre of Broadford, near the Petrol Station, on the left next door to to the church is a fairly small public toilets building with a brown wooden door. To the left of that is -
- a mysterious building with a traditional tiled roof, no windows, and no obvious door at the front. It's set back a little way so that there's off-street parking for your big Openreach van.
It is a traditional style of building for what was a UAX13, with ventilation louvres for the diesel engined emergency power generating set and a side window & door. I suspect that the power generating set has long been removed and what few equipment racks that now exist each have their own trickle-charged batteries. (No longer a big central battery set.)
Looking closely from either side, we can see that a flat-roofed extension has been built behind the original building. I would guess that there is more empty space than equipment contained within!
As always, you suspect correctly, Mr Cat. ;) :) :)
In all Exchanges, including the 'Unmanned Automated eXchange mentioned here, the large, open wet-cells that were required to a) Take the Exchange load until the generator set had got to running speed, and b) Again take the load for a required minimum 1hr period, should the Genny set fail ............ have all been replaced with the miniscule in comparison Sealed Lead Acid (SLA) batteries. Each one is slightly larger than a car battery.
Indeed, once the old Strowger, Crossbar, TXE telephony systems had been removed, vast swathes of space were left. But, and what a joy it was ...... also gone were the heat and noise !! Heaven. ;D
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I have to say UAX 13s never had a diesel generator, they relied totally on mains and battery power. Diesel generators were introduced when they were replaced by TXE2s in the seventies and eighties.
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Good info Licquorice ...... alas, I didn't start on BT until the mid-eighties on 'Power & BES', so that's all I ever knew. :)
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Found a picture online of the typical batteries.
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I can't see the details on the equipment to the right of the battery-set ….. but I'm guessing it's a rectifier unit ?? From my very poor memory, the ones I used to work on were Rec 231's and 233's ….. but we didn't have any small UAX's on our patch, so they were bigger than this unit here.
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Yes, that was the rectifier, can't remember any details though. The WB400 (cold war early warning system) kit had its own dry cells in the bottom of its cabinet.
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Just a little observation/clarification.
The UAX13 is sometimes mistakenly referred to as an 'Unmanned Automatic Exchange'. While it's true that they were unmanned - as were SAXs (Small Automatic Exchanges), Mr Cat is correct in using the term 'Unit Automatic Exchange'.
The name derives from the fact that linefinders, group selectors, final selectors and subscribers' meters for 50 lines were accommodated on a single rack. An early modular system one might say. Need 50 more lines? Add another rack.
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My thanks to B*Sheep, licquorice and 4c for their contributions. It is always helpful to hear details from those who, in their time, were a lot "closer" to the actual equipment being discussed. :)
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@BlackSheep et al
thank you for your generosity, a superb answer which draws a picture.
Basic stuff such as this isn't easily come by. I seem to remember that Kitz got a guided tour courtesy of BT. That's what I need, few of us have such an opportunity.
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From the exchange photo the equipment looks like a power plant 227 and cells secondary 22/200 eg 200 ampere/hr.
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Hehe. Really interesting to see some of the real kit in use - I'm too used to seeing everything in a lab environment.
Anyone seen this site on UAX's:
http://www.uax.me.uk/
?
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Hehe. Really interesting to see some of the real kit in use - I'm too used to seeing everything in a lab environment.
Anyone seen this site on UAX's:
http://www.uax.me.uk/
?
Yes, interesting site. Spent a lot of time adding extra A Units to UAX13s in the seventies. We also had a couple of UAX12s and the larger UAX14s.
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Just a little observation/clarification.
The UAX13 is sometimes mistakenly referred to as an 'Unmanned Automatic Exchange'. While it's true that they were unmanned - as were SAXs (Small Automatic Exchanges), Mr Cat is correct in using the term 'Unit Automatic Exchange'.
The name derives from the fact that linefinders, group selectors, final selectors and subscribers' meters for 50 lines were accommodated on a single rack. An early modular system one might say. Need 50 more lines? Add another rack.
I never knew that, regarding the true meaning of the UAX acronym. I've just done a quick search on our internal systems for 'UAX' and the first 'Hit' highlights a particular estates issue at 'xxxxxxxxx Unmanned Automated Exchange'. :-\ ::)
I absolutely understand the full and proper term, and thank you for explaining why it is properly referred to as 'Unit ......'. :) :)
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With being a modular construction, it meant that although 50 subscribers could be accomodated within one A unit, only 8 of them could make calls concurrently as there were only 8 Linefinders on an A unit.
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With being a modular construction, it meant that although 50 subscribers could be accomodated within one A unit, only 8 of them could make calls concurrently as there were only 8 Linefinders on an A unit.
Thanks for the further info, Licq ........ :)
Although a marvel of modern technology in it's day, your explanation of its limitations shows just how far we've gone in just under 30yrs !!
Who'd have thunk it ;D ;D
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In my relatively brief 40 years on the job there was one exchange that I converted from a manual switchboard above the Post Office to a Strowger, from a Strowger to a Crossbar and saw the Crossbar replaced by a digital concentrator!! Definitely come a long way.
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@licquorice -much respect.
That's how I feel when I think about the DEC VAX 11/750 that a dozen of us used to share back in 1983: 30A mains, its own room and the brute was the size of a couple of fridges, took three guys to lift it, 0.65 MIPs for a mere £150k. That compared with my wife's mobile phone : >6000 times faster (not sure, lost count some time ago) around 1000 times the RAM. The 64-bit ARM-based iPad I'm writing this on - even more frightening!
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With being a modular construction, it meant that although 50 subscribers could be accomodated within one A unit, only 8 of them could make calls concurrently as there were only 8 Linefinders on an A unit.
So the line finders stayed in the speech path for the duration of the call? That surprised me, but perhaps it is a cost of making easy-to-add modular units.
It wouldn't have been popular in the days of dial-up!
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Yes, the 8 Linefinders were hard wired to 8 of the 10 Group Selectors, which all remained in the speech path throughout. The other 2 Group Selectors (if fitted) were used for Incoming Junction (Trunk) ccts from the parent exchange.
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Hehe. Really interesting to see some of the real kit in use - I'm too used to seeing everything in a lab environment.
Anyone seen this site on UAX's:
http://www.uax.me.uk/ (http://www.uax.me.uk/)
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Yes, great site. The only working UAX13 as far as I'm aware is at the Avoncroft Museum in Worcestershire - http://www.connected-earth.com/Partnermuseums/AvoncroftMuseum/index.htm
There's also a working TXE2 mobile there.
In my relatively brief 40 years on the job there was one exchange that I converted from a manual switchboard above the Post Office to a Strowger, from a Strowger to a Crossbar and saw the Crossbar replaced by a digital concentrator!! Definitely come a long way.
I guess we must have started around the same time then. I started my apprenticeship in '65, when there were two manual exchanges in our area, and took voluntary redundancy
in '99 just as ADSL was making an appearance.
Thanks to all for the memories - I'm feeling quite nostalgic now.
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I guess we must have started around the same time then. I started my apprenticeship in '65, when there were two manual exchanges in our area, and took voluntary redundancy
in '99 just as ADSL was making an appearance.
Thanks to all for the memories - I'm feeling quite nostalgic now.
Yes, I started in '66 and stuck it out to 2007
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Wish I'd been born earlier ;) .......... this is not the BT I joined up with, and I'm sure Licq will have seen massive changes even up to 8yrs ago :no:.
Still a good company to work for, but they get sooo many things wrong on soooo many levels, with regard to their workforce. Sad really.
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I empathise and sympathise, BS - you certainly missed the best times.
By '99, the bean counters had completely transformed the ethos of the company, and not for the better. All goodwill had gone, and I couldn't wait to get out.
Yes, the 8 Linefinders were hard wired to 8 of the 10 Group Selectors, which all remained in the speech path throughout. The other 2 Group Selectors (if fitted) were used for Incoming Junction (Trunk) ccts from the parent exchange.
And here they are - in glorious stereo - Arley UAX13, Worcestershire, on 29 April 1994, a few days before it closed.
https://www.dropbox.com/s/eq872tc2knc92ds/UAX13_T002.mp3?dl=0
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The mechanical bits sound 'angry', moving so many steps per second - it sounds really fast. They really tried to get things going as fast as possible?
What metals did they use in the components to make them tough?
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One or two more questions for the BT guys, if you'd be so kind as to paint me another picture
* Where does the exchange backhaul go (physically) ?
* It's presumably a lot of fibre?
* How many fibre strands might there be?
* Does it go off in a duct?
* Following a road, or as the crow flies to some destination or other?
* Where's the next physical destination?
You've been so generous thus far. Don't wish to abuse it.
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I need to point out that I now have the answer.
* The d/s attenuation on ADSL2+ is 67 - 68 dB on each all the lines.
* On ADSL2 it is 65dB.
So Burakkucat's earlier guess of "65 - 68 dB" was spot on.
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When I said, "I have the answer", it's because now following an upgrade to ADSL2 / 21CN (discussed in another thread - http://forum.kitz.co.uk/index.php/topic,16436.msg306430.html#msg306430 (http://forum.kitz.co.uk/index.php/topic,16436.msg306430.html#msg306430)), Andrews and Arnold's clueless.aa.net.uk control panel and status server can show accurate dB figures for "loop loss", which are above 63.5 dB.
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So Burakkucat's earlier guess of "65 - 68 dB" was spot on.
It was "divined" by thinking of a number and quantifying it as a result of the extent of the tingle felt in my whiskers! ;)
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And here they are - in glorious stereo - Arley UAX13, Worcestershire, on 29 April 1994, a few days before it closed.
https://www.dropbox.com/s/eq872tc2knc92ds/UAX13_T002.mp3?dl=0 (https://www.dropbox.com/s/eq872tc2knc92ds/UAX13_T002.mp3?dl=0)
The mechanical bits sound 'angry', moving so many steps per second - it sounds really fast. They really tried to get things going as fast as possible?
What metals did they use in the components to make them tough?
The main 'stepping' sound heard is the vertical motion of a group selector, or the vertical and horizontal motion of a final selector, in response to 'loop disconnect' pulses from a telephone dial.
Due to the constraints imposed by resistance, capacitance and inductance of a line, the nominal speed is 10 pulses per second, though in practice 7 -12 would normally work.
Without these constraints, eg a linefinder, or a group selector searching for an outlet to a final selector, the speed would be - I'm guessing - maybe 50 steps/sec or more, and a uniselector probably over 200.
As for the metals, I'd never really thought about it - some info in this PDF - www.samhallas.co.uk/repository/po_docs/ep_draft_telephones_4_3.pdf
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@4candles - the thought occurred to me that there would have to be some tough materials employed.
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I built my own exchange when I was about 10 years old out of old PO relays, uniselector and old phones that came out of a factory etc. for each room around my parents house but it was not connected to the normal PO phone system.
I have still got some of the parts I use somewhere in my junk box spares box .
Some interesting links.
https://www.youtube.com/watch?v=mg0tlCEzJkI
https://www.youtube.com/watch?v=wcFpaI1Y_SE
https://www.youtube.com/watch?v=cNNKLuM8yY8
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Thanks for those videos.
One of them had a related video, which shows the system I first started work on, one or two moons ago - though it was a Plessey iSDX at the time.
https://youtu.be/dACCSguH5lo
Our labs tended to use the larger systems at this point in the video...
https://youtu.be/dACCSguH5lo?t=1422
The only clicks and whirrs in this system was from the 5.25" floppy!
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Slightly off-topic and I'm not sure that it will directly help Weaver but I note that according to the Codelook website, Broadford is down to be enabled for FTTC/FTTP as part of BDUK.
It might be worth Weaver contacting them to see if they have any plans to cover his property as well.
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He's waaaaaaaaaaaaaaaay to far from the Cab to gain any benefit if my memory serves, from tracing his line ??
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I contacted HIE or similar before Xmas, was told: FTTC will be happening in Broadford. It's all very exciting for other people. We couldn't give a stuff about rural uses such as you, after all this is only the Highlands so goodbye and enjoy others' joy.
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Just out of interest, how much would it cost to run 4.55 mi of fibre from the back of the Broadford exchange to my house Torr Gorm, the first house (northernmost) in Heasta? (Rhymes with E. haste, laced.) There are no walls, houses or other artificial barriers if you stay on the W side of the Heasta road.
The current copper cable may or may not lie on the W side of the Heasta road between Harrapul and the Water Works where the cable could advantageously go under the road at the water board bridge to cross to the E side of the road, but for what ever reason, I see that on the high moor the cable is on the E side of the road all the way til Heasta.
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And to recap the works of Burakkucat :-
http://forum.kitz.co.uk/index.php/topic,16585.msg306666.html#msg306666
http://forum.kitz.co.uk/index.php?action=dlattach;topic=16585.0;attach=18456;image
http://forum.kitz.co.uk/index.php/topic,16585.msg306752.html#msg306752
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Just out of interest, how much would it cost to run 4.55 mi of fibre from the back of the Broadford exchange to my house Torr Gorm, the first house (northernmost) in Heasta?
Looks like either £30 or £25 per metre, plus a number of other odds and sods. See .. "Excess Construction Charges" (https://www.openreach.co.uk/orpg/home/products/pricing/loadProductPriceDetails.do?data=ZdqG%2Fxv%2FjSuBEEITnogh5uNOEwQ2%2FKws5WBAVcIlcholMnGHsqdC0vzO163bJmh34D91D7M0q8u%2F%0AIlSgtIFAKw%3D%3D)
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Thanks. Shudders. Could sell the house, but then I wouldn't have anything left to run the fibre to.
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We've had quotes of that sort of magnitude for customers, for example over £200K to get service into a depot in Echt, and elsewhere from memory I think it was £85K to get to a VIPs house. Neither went ahead.
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We need a Manhattan Project, to find out how to get these per unit length costs and deployment costs down by an order of magnitude.
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Just out of interest, how much would it cost to run 4.55 mi of fibre from the back of the Broadford exchange to my house Torr Gorm, the first house (northernmost) in Heasta?
Looks like either £30 or £25 per metre, plus a number of other odds and sods.
I actually think its quite possible that the costs will be a lot less than 180K+! - though that doesn't necessarily mean cheap.
This is based on:
1. Google tells me 4.55miles is around 7.3Km.
2. Once Broadford is enabled for FTTC, I assume FTTPoD will be available.
3. The current Openreach install charges for FTTPoD are here (https://www.openreach.co.uk/orpg/home/products/pricing/loadProductPriceDetails.do?data=0WyIM7tTGGgucFf0dXUIWK4XSAplAmgrRZNg5Pk%2B5%2F%2BkRgB7BL4KNYn%2FlKx2YB4Qe6YShZ82RgLO%0AGLsH2e9%2Bmw%3D%3D)
4. FTTPoD construction charges are actually based on fibre from the nearest NGA Aggregation/fibre node (which should be near an enabled FTTC Cabinet) and I assume closer than to Weaver than the distance to the exchange.
5. BT are promising/trialling FOD2 which is supposed to be cheaper to install/use than the current FTTPoD.
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The costs for FTTPoD also say that there might be the Excess Construction Charges in addition to that variable connection charge.
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@gt94sss2 in the best case, following the public road, the current route, it could be possible to knock about 0.84 mi off the current length, but no more, because there is no civilisation closer than about 3.707 mi by public road from my house, the northernmost house in Heasta, to any kind of civilisation which I have taken as the Harapul cattle grid.
The straight line route from the back of the the exchange, which is entirely doable, straight out onto the moor and heading up to the W of the Fireach Clach, the highest point on the road cuts about a mile off the road route.
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Consult with the people behind B4RN -- and Walter -- about a DIY fibre installation project? :-\
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I worked on a residential premises a good few months ago, someone who could not get FTTC, nor her immediate neighbours (all farm dwellings).
I actually mentioned B4RN and she said they'd already had a quote off them and it was astronomical (Put your own figure on what that may be). I am in no way knocking B4RN, but I think with the distances Weaver is talking about, he would need to get the entire locality on-board to make it half-affordable ??
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Supposing I had not spent my money on various cars, etc etc
I presume there would be hassle from monopolistic landlords, at least they are few in number, and these are trying to get some payment for the right to cross their patch. I seem to remember my father getting a cheque for some 11p from a utility and always being most tickled.
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4. FTTPoD construction charges are actually based on fibre from the nearest NGA Aggregation/fibre node (which should be near an enabled FTTC Cabinet) and I assume closer than to Weaver than the distance to the exchange.
A lot of these small rural exchanges have mainly or exclusively exchange only lines, no cabinet. In Aberdeenshire what they do is stick an FTTC cabinet next to the exchange. So what I'm getting at is that the distance to the cabinet might be no shorter.
A completely different idea, how about a point to point wireless link to someone near to the exchange?
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A lot of these small rural exchanges have mainly or exclusively exchange only lines, no cabinet. In Aberdeenshire what they do is stick an FTTC cabinet next to the exchange. So what I'm getting at is that the distance to the cabinet might be no shorter.
Yes, Openreach are not allowed to install FTTC equipment in exchanges so they install cabinets next to the exchanges to get around this - I know Weaver's exchange does have some PCP's but not if his line is connected to one. The key for FTTPoD is obviously where the nearest fibre node is.
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I thought of this many years ago. Problem is, firstly need to have a very good friend really close to exchange=FAIL; secondly,line of sight = FAIL, ridge to the north of me;mains=FAIL, no mains up on the moor; reliability = FAIL, 135 mph winds will shred the hardware.
Someone else locally is already doing this, ill-advisedly called ‘SkyeNet’. They have a node in this village in fact. The wireless people that is, not the evil murdering robots from the future.