Telephone linebox question (NTE5)

We had a thunderstorm on Sunday night. Spectacular lightening all around us. I saw it approaching and disconnected the TV and computer etc. Fully expected a power cut, but it didn't. But on reconnecting the computer after the storm had passed, no broadband connection, no dialing tone, no nothing. Quite dead. Even the test socket in the linebox was dead. However, ringing neighbours on our mobile showed we were the only ones without a land line connection. Engineer duly arrived yesterday; linebox had blown. Replaced it, and all now OK.
But what is it in the linebox that blows? A quick internet search talks about spark gaps and the like, but I haven't found anything that suggests a fuse. So what blows, and why is it so integral to the box that the whole box has to be replaced?
--

Chris

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On Thu, 14 Apr 2016 10:02:11 +0100, Chris Hogg wrote:

There's a 'lightning arrester' (they probably call it something else) across the line. I suppose it could be a MOV but I've no idea really.
I would guess that could go short circuit. As for replacing it, that would involve soldering, and more effort 'cost' than a new box.
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Seems likely. If it did, it would short the line and render it inop (it would give 'busy/engaged' if called from another line.)
<http://www.wppltd.demon.co.uk/WPP/Wiring/UK_telephone/a_Phone_wiring_cc t_diagram.gif>
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On Thu, 14 Apr 2016 10:29:35 +0100, Mike Tomlinson

That makes sense. I tried dialing our land line number with our mobile, and got a recorded message that the line was engaged. So the surge suppressor was blown; presumably not a direct hit on the telephone line (overhead, hereabouts), as I would have expected our neighbours to be knocked out as well, but enough of an EMP to blow the suppressor.
Thanks both.
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Chris

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On Thu, 14 Apr 2016 12:40:27 +0100, Chris Hogg wrote:

else)

really.
Spark gap and it is what it says not a MOV.

Did the message use the word "engaged" or "unavailable". A line actually making a call would normally return engaged tone not a recorded message unless the line has a provider based answering service.

Or vapourise the tracks from the socket pins to components. Replacing the whole NTE is simply quicker and cheaper than the time taken to diagnose and fix a fault with it.
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Dave.
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On 14/04/2016 13:06, Dave Liquorice wrote:

Neither of those, it's a gas discharge tube (GDT).
Think of it as a butch neon tube, or for more info try https://www.bourns.com/pdfs/bourns_gdt_white_paper.pdf
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Andy

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On Thu, 14 Apr 2016 13:44:47 +0100, Andy Wade

So how does it blow into an unrecoverable state? Or would it be DL's vaporised tracks that crippled the box?
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On Thu, 14 Apr 2016 13:44:47 +0100, Andy Wade wrote:

Posh name for a spark gap. B-)
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On Thu, 14 Apr 2016 20:04:02 +0100, Dave Liquorice wrote:

Is exactly right! :-)
On a BT exchange, you'd expect to receive an unavailable announcement or NUT when calling a number that has a loop fault (unless called within 60 seconds of the fault developing or after the S&Z cycle period if the fault occurred whilst on an outgoing call and the called number hung up on the call).
Getting PET for hours/days/weeks of such an "off hook" fault is typically the case with Talktalk exchange equipment (and possibly also the case with all of BT's competitor telco exchange equipment).
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Johnny B Good

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Just shows that the lightning arrester across the pair can work, I still think you are lucky there wasn't damage done to your router and phones.
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Graham.

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On 14/04/16 15:05, Graham. wrote:

+10
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Future generations will wonder in bemused amazement that the early
twenty-first century’s developed world went into hysterical panic over a
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On Thu, 14 Apr 2016 16:13:18 +0100, The Natural Philosopher

Years ago I used to maintain a Philips office phone system in rural Wales. It got zapped frequently, and each time the whole unit had to be replaced. So when it happened again we took a closer look, and one of the BT lines feeding it ran very close to a long run of wire fencing. After re-routing this dropwire, it never again caused trouble.
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escribió:

He said he had disconnected those.
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"Rod Speed" wrote in message escribió:

Well BT Openreach replaced our NTE5 front plate today - telephone no dial tone or incoming calls, Internet connection working fine. Presumably the LF part of the filter - can't be much to them so quite surprised it was that that had popped it's clogs
Andrew
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On Fri, 15 Apr 2016 13:29:26 +0100, Andrew Mawson wrote:

Lack of a DC path kills the phone but ADSL/VDSL uses radio frequency carriers and can get across small gap. This knocks the speed back but the 'net still be there.

They are actually quite a complex of capacitors and inductors, I'd still go with a fried track breaking the DC loop. Especially if the 'net was still there at full whack.
Is the faceplate one with a filtre in it? Sort of surprised BT replaced that, they only have a requirement to deliver POTS to the test socket behind it. Ok the facplate is part of the NTE but it only needs to provide POTS.
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"Dave Liquorice" wrote in message

Yes Internet was still going as strong as ever (21 Mb/s). NTE5 faceplate has the filter in it and is BT supplied so surely they'd have to fix it as it is their property ? Sadly no fibre - our fibre equipped cabinet is over a mile away :(
Andrew
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On Fri, 15 Apr 2016 22:33:30 +0100, Andrew Mawson wrote:

only

Not "Superfast Broadband" then. Has to be over 24 Mbps to qualify for that title. 4 to 5 Mbps ADSL2 here and no chance of ADSL2+ or VDSL, not that either of those would make much difference to the speed at the end of 3.5 km of line.

I guess so, things move on. Is the default now a filtered face plate?

Fibre has a range of 10 km + and thats with 32 way PON split. Take out the split and several to many 10's of km is possible. Have you asked BT for a fibre connection? You find that there is a fibre node nearer to you and install costs may only be a grand.
Or are you using the term "fibre" to mean VDSL? Which at a mile is going to have degraded to more or less the ADSL2+ speed that you, presumably, currently have.
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"Dave Liquorice" wrote in message

Dave,
It's a rural situation here albeit only 50 miles from London. Recently BT Openreach have installed two VDSL cabinets in the village on minor roads, adjacent to the original voice cabinets. So it's fibre from the tiny village exchange to the new VDSL cabinet, then copper mainly underground but some overhead the 1.2 miles from the house to the cabinet.
As the farm gate is on one of the only two trunk roads in East Sussex, and our nearest neighbour is half a mile away, I see no prospect in the sensibly near future of fibre getting much closer - they won't dig up a trunk road to equip one house !
Andrew
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On Sat, 16 Apr 2016 08:43:47 +0100, Andrew Mawson wrote:

on

This is what normally happens though they did plant a number of new copper line cabinets around here as the cable joints were in chambers.

The fibre cable may not pass through that exchange at all and even if it does it'll only be a patch panel to ease utilisation of the currently dark fibres in those cables. The fibres from the VDSL cabinets around here go to Hexham 40 odd km away before they hit any active routers/switces WHY.

e

That's the PITA, BT use 1 km line length from the cabinet as a rough guide for the provision of "Superfast Broadband". Our line was an "exchnage only line" no cabinet, so no VDSL. However they installed a cabinet outside the exchange, trouble is that is 3.5 km away. There are occasional mutterings of G.Fast but from what I've read about that it just bumps up the speed available over the first few hundred (tens?) meters of copper, does SFA for those more than a 1 km or so from the cabinet.

e

You may find that fibre is already running along those roads, in fact I'd almost put money on it. All the exchanges have been fibre linked for a very long time, though some remote tiny "garden shed" exchanges might be on a radio link. Have a look for rectangular manhole covers every 200m or so, either in the road surfce or verge. Ones in the verge might be hard to find as they are so rarely opened they become completely over grown. Probably have "Post Office Telephones", "GPO" or "BT" markings. Then you need to find the nearest "fibre node", this is point where the fibre cables are jointed to extend on or to split. This gives access to the fibre cable and the possibilty of "Fibre to the Premisis On Demand" with the exccess construction only charged from the node, not the nearest exchange with (customer) fibre access.
There is a brand spanking new fibre cable running 10' from our front door, to feed the VDSL cabinet in the village. The team installing the duct for it said that there was to be a fibre node in the next chamber upstream, ie 200m away. So FttPOD might be possible or FttRN (Fibre to the Remote Node). That is a small robust VDSL box, designed to live up a pole or in a hole serving a small number of customers. I believe they don't need a mains electricity supply, being powered from the connected customers over the copper pair but not sure if BT are using that.

They will if you pay... It's about £100/m to dig up a road. B-)
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Dave.
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On Sun, 17 Apr 2016 02:00:10 +0100 (BST), Dave Liquorice wrote:

Forgot to mention Openreach have a scheme called "Community Fibre Partnership". If a group can be formed, in a suitable area, to come up with some fraction of the install cost Openreach will install it.
http://www.homeandwork.openreach.co.uk/OurNetwork/CommunityFibrePartne rships.aspx
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