This matches with what I've seen/heard/read - the clicking is the NTD turning
off/on power to the DPU, while it tries to check if it's coming online.
We had a DOA DPU and have had one since after a storm, in ... under three
months.
James
On 2021-01-25 09:30 Matt Perkins wrote:
> There’s
Be great to see a few high res-shots inside.
Matt
On 25/1/21 10:45 am, James Hodgkinson wrote:
This matches with what I've seen/heard/read - the clicking is the NTD turning
off/on power to the DPU, while it tries to check if it's coming online.
We had a DOA DPU and have had one since after
There’s nothing quick about a disconnecting relay. But I do have the reports of
them clicking so perhaps power is applied and they are looking for some
condition that does not appear so power is removed a d re-applied. Whatever
condition they are looking for can not be sensed due to the fault
There is definitely a relay internally, not sure what it's actually there for
though - could be for applying power to the line when attempting to power the
DPU, if a short is detected it can disconnect quickly.
Kind regards,
Thomas Jones
-Original Message-
From: AusNOG On Behalf Of
They had a few hundred to replace in the eastern suburbs in the first week of
Jan the cable there is almost all underground. If anyone has one and can post a
detailed photo of the PCB we can get to the bottom of it but suspect the HV
protection is non existent.
I have heard mention from
Mea Culpa.
That makes perfect sense. I was considering it from an RF perspective
wherein the mass of earth would theoretically shield the buried
copper. I'd failed to consider that in the case of a ground strike the
buried copper presents a low-resistance path through the lumped
resistance of
I don't know if it's related, but last weekend we had a NBN FttC
device fail following a storm, but it was the DPU in the street, not
the NTD. There was power loss, but no lightning in the immediate area.
They said due to equipment shortages it'd be 3 days for a replacement,
but it was there the
Yes it really is that bad. Word is they are replacing thousands of NTD's
every week. It appears the design adopted is very sensitive to potential
difference from induced current flows over relatively short cable lengths.
Faster Cheaper Better. Thanks Malcolm.
Matt
On 22/1/21 11:30 am,
On Fri, 22 Jan 2021, John Edwards wrote:
Underground copper is probably more vulnerable than aerial to lightning.
Lightning strikes the ground, not the copper, but a voltage gets induced
in the copper due to the nearby electromagnetic charge - something that
doesn't happen in air because
All of the DSLAMs that Australian carriers are throwing in the bin right
now have $20 gas-discharge lightning arrestors on every port to comply with
TEBA rules around LSS connections.
I imagine that FTTC has no such requirement because there is no expensive
voice exchange to protect.
Underground
I wonder if it has anything to do with the old legacy copper that was
previously hooked up to the DPUs, which the NCDs trigger a cutover from.
There could potentially be rather a lot of it there, not necessarily
grounded if the old legacy infrastructure has been partially removed, so an
induced
Yeah, I'd say that's a good bet.
Aerial lead-ins are always going to be more susceptible to induced
spikes from nearby lightning than buried cable.
On Fri, Jan 22, 2021 at 11:30 AM wrote:
>
> On Friday 15th we had 30 FTTC NCDs "fried"
> in a single 1km2 area due to an electrical storm.
> No
On Friday 15th we had 30 FTTC NCDs "fried"
in a single 1km2 area due to an electrical storm.
No other devices were impacted in the affected households and
damage occurred irrespective of whether NCDs were plugged to
surge protectors or not.
It seems unlikely that lightning hit lead-ins for the
The DPUs being back-fed from the houses they provide service I’d suggest is the
main reason - ADSL modems just had the ADSL signal to contend with, whereas
back feeding power means you’ve got the DPU, with power across the 4 Cu lines
into the houses and the power grid in four houses connected
Dundas NSW - Have had three jobs at the one place since xmas including a
fire as the result of lightning - I recall there is another fellow on list
from the area maybe has similar stories - The process is annoying for the
FTTC (can be 5 days waiting, for a quick hardware replacement from the good
Maybe it's the fact that the NTDs are being powered by residential houses
instead of the provider's exchanges, and *very* few people in reality use
*good* surge protectors - let alone know they have to replace them after a hit,
or identify when they're no longer working?
The power's still
Agree, and as per the text below (cut 'n pasted from:
https://www.cablinginstall.com/cable/article/16465312/ground-potentials-and-damage-to-lan-equipment),
maybe part of the problem is that each house has a different earth
potential?
I'm not an electrical engineer - so I'm assuming the below is
> -Original Message-
> From: AusNOG On Behalf Of Karl Auer
> Sent: Thursday, 21 January 2021 11:24 AM
> To: aus...@ausnog.net
> Subject: Re: [AusNOG] Lightning and FTTC - is it really this bad?
>
> There are two ways in to the CPE - the FTTC connection and the power
> supply to the CPE.
Yes Mark, I've heard of it ;)
I guess my point was - why is (is it?) FTTC somehow apparently more susceptible
to discharge issues than POTS was/is. Perhaps I am getting the wrong impression
from the article.
Regards, Troy
Brevity is the elixir of life.
Father Hector McGrath, Pixie 2020
The FTTC NCD's in the customer premise reverse power the DPU in the
street(curb). Up to 4 premise connected to the DPU can share the reverse
powering of the DPU to allow lower power draw from each user's NTD and also
providing a form of redundancy for the users connected to it. So I'd hazard a
On Thu, 2021-01-21 at 11:04 +1100, Jrandombob wrote:
> Even in a high lightning area, as Damien said previously, if anything
> FTTC ought to be LESS susceptible (assuming of course the devices are
> well designed) to lightning owing to the shorter cable runs.
There are two ways in to the CPE -
Yeah, sounds to me like the NTDs just aren't very well designed.
Even in a high lightning area, as Damien said previously, if anything FTTC
ought to be LESS susceptible (assuming of course the devices are well
designed) to lightning owing to the shorter cable runs.
On Thu, Jan 21, 2021 at 10:50
Ever tried to convince NBNCo that they got incorrect maps from Telstra and
that HFC will not be a suitable replacement for a single property with
capacity for six legacy phone lines (terminating in different rooms)? They
are not known for their ability to solve problems that deviate from their
As somebody who lives in one of the areas that gets affected a lot, and that
the article was mostly written about I believe, I can tell you that there are a
lot more NTD’s getting damaged than there was ADSL modems.
I can’t explain it either, it shouldn’t be happening, however people with
Damien, I agree with you. Lightning is going to be causing the same issues it
always caused regardless of the technology; telegram, POTS, ADSL or VDSL from
the curb or cabinet – nothing’s changed because there’s still copper conductors
in the ground.
I smell a lot of agenda pushing and bias
Yeah it really didn’t make sense to me. How is a product which only has a
TINY bit of copper compared to FTTN and indeed the older POTS network, SO
much more susceptible to lightning strikes? I mean, it’s Fibre to the pit,
and then one breakout box is running four(?) homes, with maybe 100-150m
I'm confused as to how FTTC would suffer more from lightning strike related
issues than other ground conducting technologies?
Is it something about the Blue Mountains in particular, or is this article
rubbish?
(Paywall, open in incognito if so inclined)
Excite@Home (which became Optus@Home, which became Optus Cable Internet)
had a contractual obligation on the customer to leave the cable modem
plugged directly into the wall socket they installed, specifically
prohibiting the installation of a surge protector/arrester.
They then tried to charge
Heard of ADSL? POTS?
If the Internet was only meant to run over fibre, there wouldn't have been
any ARPANET or Internet before the late 1980s or early 1990s.
Fun fact, RFC1 was written on a typewriter in a bathroom in 1969, because
Steve didn't want to disturb his flatmates.
Hi Troy,
Lightning has always been an issue for the copper network – the old adage
“don’t use the phone in a storm” comes to mind.
Certainly where my mum is, in Springwood, the copper is above-ground-- you
often see a 100-pair floating off the power poles, with the house pair coming
from a
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