speed test...

[Don Y]

On 9/17/2023 7:37 AM, Martin Brown wrote:

.. *to* the village?  Are there so few subscribers there that the CO
isn\'t located *in* the village?  (\"village\" has different connotations,
depending on where it is used, here; some villages are the size of towns;
some towns the size of villages)

UK \"village\" has some ambiguity too. Modern ones can be legally up to 5k which
means there are a lot of new builds with populations 4,999.

Sheesh! \"Sorry, you can\'t move here -- we\'re already at capacity!\"
<rolls eyes>

Mine is a former medieval village in the old sense (arguably now a hamlet) with
about 250 people in ~5 square miles. Mostly in a linear development along the
main street apart from the farms.

Wow! OK, that\'s tiny. My hometown was ~1500 folks in about 400 homes.

It was a fair bit 2-3x bigger before the black death struck it...

Most COs (in the places I\'ve lived) have lines coming into a
room in the basement, then up to a \"wiring room\" where all of
the pairs are laid out (on punchdown blocks?).

Is a CO what we would call a cabinet? Where the main trunk line back to the
exchange is terminated and the local consumer circuits start?

Sorry. \"Central Office\". It\'s close to what you would call an \"exchange\"
but an \"exchange\" has also historically meant the first three digits of
a (3+4) digit phone number. Nowadays, large numbers of (copper)
circuits are handled in a CO which may span multiple \"phone number
prefixes\".

If so that is what is unusual about our provision - there is no cabinet the
lines go all the way back to the exchange. That is unusual here...

It would be unusual here, in newer developments. My home, growing up,
was like that -- wire off telephone pole into home, other end at
the \"closest\" CO (which, back then, was a step-by-step office...
\"Valerie 8\")

When/if they ever surface, I\'ve never directly observed.  And, nowadays,
you don\'t know if they haven\'t run fiber out to a remote concentrator...

That in the UK would be FTTC (VDSL fibre to the cabinet) with copper circuits
to the consumers. Putting these onto Digital Voice VOIP makes them incredibly
useless since even if the consumer end has a UPS the powered cabinet needed for
FTTC does not have any back supply.

Ah! Well that\'s a shortsight! I wonder how CATV and cell towers
address power issues? The towers seem to have tiny \"support buildings\"
(if at all) barely larger than a clothes closet!

That service is Digital in Name Only or \"DINO\" it combines all the worst
characteristics of VOIP (fails without power) without eliminating the pesky
final mile of ageing copper that carries the VDSL signals.

Earlier versions (here) also had problems with acoustic modems.

POTS generally continues to work even when DSL is down (except if there is a
fine break small enough for RF to jump the gap capacitively). Most importantly
it still works when the mains has failed (and for a decent length of time too -
exchanges have largish battery backup systems).

... as long as the PHYSICAL line quality hasn\'t degraded.

Here, the CO is actually battery powered with the batteries
continuously being charged (in the event mains power fails, a
small, jet-powered genset picks up the load; in ages past,
the billing computer might not be thusly backed up so
\"free long-distance\" :> )

A cell phone subscriber could hedge his bet by picking two
different carriers and HOPING they didn\'t share towers.

A CATV subscriber would be entirely at the mercy of the provider
as only a single provider is allowed to operate in most
areas (e.g., towns)

are a bit unusual in that our lines are archaic \"Exchange Only\" lines with
no cabinet between us and the exchange.

So, any line repair/reconfiguration is done AT the CO?

There is no CO the lines run right back to the exchange.

my CO = your exchange so, yes, any reconfiguration would be
done back at the exchange/CO.

Seeing a wiring cabinet *in* a neighborhood is a new
thing, for me. Previously, I\'d only seen them in businesses
(PBX).

That is the meaning of an exchange only line. They are a nightmare for VDSL
operation because of the crosstalk they induce inside the exchange. The
standard fix is that they install a new powered FTTC cabinet nearby and run
anyone nearby taking the VDSL service to that.

I\'ve not been *in* a CO/exchange for decades so can\'t speak to
their current practices.

But, given TPC\'s tendency to roll out different solutions to
problems, over time, I can only imagine it is a hodge-podge of
kludges (that all \"made sense\", at some time)

There\'s a large (20 sq ft) wiring cabinet at the entrance to our
subdivisions that terminates all of the pairs from the CO *to*
the pairs feeding the subscribers.  There is ALWAYS a telco
service vehicle parked nearby \"fixing\" something (I\'m guessing
200 homes in the subdivision?)

That is about the size of our entire local exchange including its battery room.

By 20 sq ft, I meant the panel is 4x5 ft (by about a foot deep?)

My fibre service doesn\'t go to that exchange at all but to a much larger
exchange ~12 miles away in the county town.

Electricity also comes in overhead on the same set of poles which makes it
difficult for the telco - they have to bring in a cherry picker to work on
their signal level cables at height because of the live wires!

Hmmm... the places I\'ve lived with overhead wiring have usually
had the high tension wires at the top of the poles (imagine a T)
with cable and phone down much lower -- like halfway.  They transit
to the home over separate paths so even if you had to access the
cable at the house, there would be sufficient clearance from the
mains feed.

The convention in the UK is horizontal mounted wires implies medium high
tension 33kV or thereabouts and vertical mounted wires are consumer 240v
distribution. I reckon the lowest now uninsulated hot cable is only about 2\'
above the telecoms line. Poles are also marked \"do not climb\" for other reasons
of age and decrepitude.

On *poles*, that is probably the case -- mostly. In many areas, a pole-mounted
transformer will tap off *a* set of high tension wires and then route it\'s
secondary down the pole for underground transit to the subscriber (in a
suitably sized conduit).

In some cases, the secondary lines will fly (\'horizontally\") to the
subscriber. The phone line will parallel this flight.

But, there are often multiple sets of high tension wires on a pole
(and several different types of poles). I think the goal being to
reuse existing pole PLACEMENTS as much as possible (i.e., better to
upgrade a pole to support additional conductors/uses than to
ADD a nearby pole to replicate teh functionality)

From <https://en.wikipedia.org/wiki/Utility_pole> see
<https://en.wikipedia.org/wiki/File:US_utility_pole_-_labeled.jpg>.
Each of the \"common\" uses of a residential pole are illustrated.

Water frequently infiltrates our buried cables (including the 100+ pair
that runs the length of the street, below grade).  So, a (rare!) rain
can leave you with a noisey line that resolves itself BEFORE the lineman
can get around to actually checking the line, in person.

That is pretty much the situation here except that it is a lot wetter and
the groundwater is mildly alkaline and so corrosive.

Ours is classified as \"slightly to very strong alkaline\" with a pervasive
layer of calcium carbonate some 6-12 inches below the surface.  The soil
temperature is relatively high (70-80F) tracking our average air
temperature (~75F)

It is a lot colder than that here so penetrating ground frosts also play a part
in prizing wet crimp joints apart.

Yes. CATV and phone are barely below surface level. I think power is
down ~3 ft with gas and water at comparable depths.

The advent of cell phone technology took a lot of pressure off of
POTS; folks could just discard their pairs, making them available
for the next house up or down the street.

That is happening here too. In fact apart from going with BT you automatically
lose your landline number if you take full fibre internet.

It was *supposed* to be that you could take your number \"anywhere\".
But, there are some special cases that still apply.

The naming convention is pretty silly too - they first sold FTTC as \"fibre\" so
they now have to call true fibre services \"full fibre\".

Like \"high speed\" USB?

[I\'m waiting for \"ludicrous speed\" to find its way into the vernacular, Mel.]

You are supposed to do this before reporting a fault.

Yes, and because a RJ11 *jack* is presented, you can
carry a station set out to the TNI and connect to the
network directly to convince yourself that the
problem lies with the provider (or in the home).

UK has its own peculiar BT connector - not RJ11 although adapters are available
(thought nothing like as peculiar as Belgacom\'s connectors).

It (RJ and related) are an unfortunate choice. They are TOO cheap.

Here, the crimp connections would happen on punchdown (66/110) blocks.
The pedestal wiring is less disciplined; I have no idea how they
keep track of which pairs they split off of the main cable at
each pedestal!  (and wonder if there is ANY documentation of this??)

I have wondered about that too. They do seem to know which line pair is which
without having to put a trace signal on most of the time.

We\'ve had high tension lines replaced several times on our (short)
street. The SOP is to phone into <some guy> who maintains the
maps prior to making any changes to the wiring: \"I\'m about
to disconnect the B conductor from transformer 123...\" In theory,
this keeps the maps current (to within minutes).

But, often, I can overhear a \"disagreement\" between the linesman
on the ground and the map manager over which wire goes where:
\"I have B feeding transformer 124 *south* of your location.
Are you saying it actually feeds 122 NORTH of there?\"

The linesmen all KNOW not to trust the maps -- as it\'s their
ass that\'s on the line if there\'s a mixup between the documentation
and reality!

OTOH, I know how hard it is for me to keep my cabling diagrams
up-to-date. And, *I* am the only person dicking with it!
A city-scale operation has got to be a nightmare considering how many
subcontractors may have a hand in the mess!

 

[Don Y]

On 9/17/2023 12:56 PM, Don Y wrote:

If so that is what is unusual about our provision - there is no cabinet the
lines go all the way back to the exchange. That is unusual here...

It would be unusual here, in newer developments.  My home, growing up,
was like that -- wire off telephone pole into home, other end at
the \"closest\" CO (which, back then, was a step-by-step office...
\"Valerie 8\")

Actually, that *should* have been \"VAlerie 8\" but our exchange was
so small that a digit absorber allowed it to be implemented as
\"Valerie 8\".

[I can still recall giving my phone number out as \"VA...\"]

 

[TTman]

On 12/09/2023 15:18, John Larkin wrote:

I signed up with Comcast for, I think, 30 megabit cable internet. I
had a service problem a while back so they upgraded \"for free\" to 50.
I just ran a speed test and it\'s 920+38 Mbits. This is with a CAT5
cable right from their modem.

At work, we have a MonkeyBrains dish. We pay for 50+50 and get
500+500.

This seems to be a trend, much faster internet than we signed up for,
same price. The backbone fibers must be moving petabits.

Maybe you signed up for megabytes and you\'re measuring megabits ? 8 data
1 start 1 stop ?

--
This email has been checked for viruses by Avast antivirus software.
www.avast.com

 

[John Larkin]

On Sun, 17 Sep 2023 23:14:00 +0100, TTman <kraken.sankey@gmail.com>
wrote:

On 12/09/2023 15:18, John Larkin wrote:
I signed up with Comcast for, I think, 30 megabit cable internet. I
had a service problem a while back so they upgraded \"for free\" to 50.
I just ran a speed test and it\'s 920+38 Mbits. This is with a CAT5
cable right from their modem.

At work, we have a MonkeyBrains dish. We pay for 50+50 and get
500+500.

This seems to be a trend, much faster internet than we signed up for,
same price. The backbone fibers must be moving petabits.



Maybe you signed up for megabytes and you\'re measuring megabits ? 8 data
1 start 1 stop ?

All megabits. And it\'s not an RS-232 interface.

I don\'t know how cable modems work. Some complex constellation
modulation I suppose. Maybe some 8b10b in there somewhere.

 

[Muhammad Nur Cahyo]

https://www.papandayancargo.com/
https://www.papandayancargo.com/ekspedisi-surabaya-makassar/
https://www.papandayancargo.com/ekspedisi-surabaya-banjarmasin/
https://www.papandayancargo.com/ekspedisi-surabaya-balikpapan/

 

[Muhammad Nur Cahyo]

https://www.papandayancargo.com/
https://www.papandayancargo.com/ekspedisi-surabaya-makassar/
https://www.papandayancargo.com/ekspedisi-surabaya-banjarmasin/
https://www.papandayancargo.com/ekspedisi-surabaya-balikpapan/

 

[Jan Panteltje]

On a sunny day (Sun, 17 Sep 2023 11:08:27 -0700 (PDT)) it happened whit3rd
<whit3rd@gmail.com> wrote in
<13fb7301-2990-4318-9d6f-c4ff734b4791n@googlegroups.com>:

On Sunday, September 17, 2023 at 3:32:41 AM UTC-7, Jan Panteltje wr=
ote:
On a sunny day (Sat, 16 Sep 2023 22:38:41 -0700 (PDT)) it happened whit3r=
d
whi...@gmail.com> wrote in
08d599b3-ab2b-4526...@googlegroups.com>:

On Saturday, September 16, 2023 at 10:05:07 PM UTC-7, Jan Pantel=
tje=
wrote:

SF likely will not exist in a couple of years...
I was just reading that California is going to sue five big oil and ga=
s companies for heating up earth:
ExxonMobil,BP, Chevron, ConocoPhillips and Shell.

They should be grateful to those companies ...

Gratitude for products, but not for byproducts. The purpose of suing is =
to get a court to
consider the issue of those byproducts having a large-scale pollution co=
st, that SHOULD
be accounted for in economic decisions, and paid for by the customers of=

\'big oil and gas companies\'. If those bit companies add the cost of
pollution to their products\' costs, the suits will have satisfied Califo=
rnia,
and reward the oil-and-gas folk a bit of repayment for their collection =
of the new tax...

The money losers, will be Jan Panteltje and associates. We\'re all his as=
sociates on
this forum, of course.

Well, from the POV from reality,

Oh, that\'s bad wording; reality is large, offers many points of view, not j=
ust one.
A lawsuit means there\'s at least two to be considered here.

let\'s just all those companies as from now stop supplying California
with oil, gas and ALL byproducts from oil, such as plastic, energy,
everything.

... which will not terminate the suit, since damage is present and unremedi=
ed, not just
potential for the future

The lynching of those political insane CO2 clowns would be...

a hate crime?

No self protection


You know, making money -using lawsuits and lawyers- does not produce anything
no wonder US debt keeps increasing!
Simple math!!

 

[Jan Panteltje]

On a sunny day (Sun, 17 Sep 2023 10:28:13 -0700) it happened John Larkin
<jjlarkin@highlandtechnology.com> wrote in
<lmcegi570nu4a1v3upahkos9uuor6qioam@4ax.com>:

San Francico has stunning views that are usually ruined by hideous
wiring. It\'s being undergrounded, which should be mostly done in a
couple of hundred years.


SF likely will not exist in a couple of years...
I was just reading that California is going to sue five big oil and gas companies for heating up earth:
ExxonMobil,BP, Chevron, ConocoPhillips and Shell.

They should be grateful to those companies that made California liveable and the industry and jobs they created,
The complete insane climate idiots that infected politics using CO2 witch hunts means the end of civilization.

Electing greenie morons will change, as people sit hungry in the cold
and dark in their dead Teslas.

SF will exist for a long time. Lots of people will always want to live
here.

Sure Su[p]perman will come to the rescue when the Andreas fault is triggered?

Sure, we\'ll have another big one eventually. Climate Change doesn\'t
cause earthquakes, although some idiots have claimed it does.

All thing in nature are interacting.
Continental shelfs move and cause earthquakes, create mountains that then change weather etc..
Vulcanos are created by the movement that then change the atmosphere,, land turns to sea and the other way around.
Weather lets us drill for oil and change the land and coast lines, actions that may well trigger earthquakes..
We -are- part of it all.
As do our nuke test / wars.,..

Since the 1989 quake, building codes here have impoved, both for new
construction and for older structures. Wood frame houses are required
to be reinforced against ground-floor-garage \"soft-story\" failure and
bricks must be reinforced. Our house was built in 1992, and it has a
steel frame concreted into bedrock, with plywood shear walls. Our real
concern would be a giant fire.

We spent a goodly part of a megbuck to harden our company building.

Current geology speculation suggests the big dangers are earthquake in
southern California and a massive tsunami in Washington and Oregon.

A big quake in mid/eastern USA, like the one in 1811, would be
ghastly. Too many unreinforced brick and stone structures.

England has lots of stone structures but doesn\'t get serious quakes,
but many places in europe do both.

Here massive flooding in the future due to rising sea levels is expected.
So mass migration will follow...

Then warm periods, ice ages.. comets .. changes in the sun.. it is all dynamic
we participate and are part of it, in the end just a transient (like the dinos)
in the universe full of stars and other mysterious (to us) things.

 

[Martin Brown]

On 17/09/2023 16:15, John Larkin wrote:

On Sun, 17 Sep 2023 15:32:28 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 16/09/2023 12:19, John Larkin wrote:

I collect pictures of disgusting wiring.

https://www.dropbox.com/scl/fo/rdbz4ayuw0w60ch1f4dot/h?rlkey=k14c22nkj1leclay7itlpk28z&dl=0

It seems to me a miracle that telecoms stuff actually works!

Our utilities, including cable/internet, are actually quite reliable.
I can\'t explain that.

Our cable modem hangs up once in a while, but that\'s just the usual
software bugs. A hard power cycle fixes that.

When I had a cable modem in Belgium it was so reliable that I never had
to look at it until it was time to move out. The PSU brick for it ran so
hot that the label on the outside of it was slightly scorched! Scary!!!

My fibre modem hasn\'t been rebooted since installation apart from when
it was unplugged for rearranging my office furniture. It is very stable.

ADSL links used to die at least every couple of months with router
firmware either going unresponsive or claiming perfect signal synch but
no data transfer so incrementing hard unrecoverable error seconds in
realtime. I always got a few of those per day in normal operation.

--
Martin Brown

 

[John Larkin]

On Mon, 18 Sep 2023 10:36:03 +0100, Martin Brown
<\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 17/09/2023 16:15, John Larkin wrote:
On Sun, 17 Sep 2023 15:32:28 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 16/09/2023 12:19, John Larkin wrote:

I collect pictures of disgusting wiring.

https://www.dropbox.com/scl/fo/rdbz4ayuw0w60ch1f4dot/h?rlkey=k14c22nkj1leclay7itlpk28z&dl=0

It seems to me a miracle that telecoms stuff actually works!

Our utilities, including cable/internet, are actually quite reliable.
I can\'t explain that.

Our cable modem hangs up once in a while, but that\'s just the usual
software bugs. A hard power cycle fixes that.

When I had a cable modem in Belgium it was so reliable that I never had
to look at it until it was time to move out. The PSU brick for it ran so
hot that the label on the outside of it was slightly scorched! Scary!!!

My fibre modem hasn\'t been rebooted since installation apart from when
it was unplugged for rearranging my office furniture. It is very stable.

ADSL links used to die at least every couple of months with router
firmware either going unresponsive or claiming perfect signal synch but
no data transfer so incrementing hard unrecoverable error seconds in
realtime. I always got a few of those per day in normal operation.

Our Comcast box downloads its software from the mother ship, every
time it powers up. That takes about 15 minutes. I asssme they are in
the usual constant-upgrade bug manufacturing mode, as downloaded
software usually is.

If it\'s easy to fix, it\'s easy to break.

 

[Martin Brown]

On 18/09/2023 15:33, John Larkin wrote:

On Mon, 18 Sep 2023 10:36:03 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

My fibre modem hasn\'t been rebooted since installation apart from when
it was unplugged for rearranging my office furniture. It is very stable.

ADSL links used to die at least every couple of months with router
firmware either going unresponsive or claiming perfect signal synch but
no data transfer so incrementing hard unrecoverable error seconds in
realtime. I always got a few of those per day in normal operation.

Our Comcast box downloads its software from the mother ship, every
time it powers up. That takes about 15 minutes. I asssme they are in
the usual constant-upgrade bug manufacturing mode, as downloaded
software usually is.

Ouch! That is a royal PITA. Mine has to have its firmware updated every
now and then if a vulnerability is found and/or exploited but it boots
in under a minute from whatever internal SSD/memory stick it has.

It issues dire warnings about not switching it off during an update.

> If it\'s easy to fix, it\'s easy to break.

Too true

--
Martin Brown

 

[Don Y]

On 9/18/2023 9:06 AM, Martin Brown wrote:

Ouch! That is a royal PITA. Mine has to have its firmware updated every now and
then if a vulnerability is found and/or exploited but it boots in under a
minute from whatever internal SSD/memory stick it has.

It issues dire warnings about not switching it off during an update.

I wouldn\'t design any new application to run out of FLASH.
If the flash was fast enough for XIP, then you\'d worry about
read wear (how do you recover if your media is \"suspect\"?)

And, RAM tends to be faster so you\'re going to WANT to transfer
your code into RAM, regardless...

If you have a decent size pipe, load the image over the wire.
This ensures you retain control over the product -- cuz it has
to \"reauthorize\" itself when it connects to the image server!
Particularly valuable if you treat \"products as services\" (the
new trend).

This lets you reduce your FLASH requirements to whatever is
available in an SoC and spend it doing POST/BIST instead of
*hoping* the application image will (always) fit in FLASH
(and never be corrupted).

[And, products that are \"islands\" will be deprecated as everything
WANTS to talk to other things... you just haven\'t, yet, figured out
*why*!]

 

[Lasse Langwadt Christensen]

mandag den 18. september 2023 kl. 20.51.22 UTC+2 skrev Don Y:

On 9/18/2023 9:06 AM, Martin Brown wrote:
Ouch! That is a royal PITA. Mine has to have its firmware updated every now and
then if a vulnerability is found and/or exploited but it boots in under a
minute from whatever internal SSD/memory stick it has.

It issues dire warnings about not switching it off during an update.
I wouldn\'t design any new application to run out of FLASH.
If the flash was fast enough for XIP, then you\'d worry about
read wear (how do you recover if your media is \"suspect\"?)

read wear? you have a single example of a flash with a limit on reads?

And, RAM tends to be faster so you\'re going to WANT to transfer
your code into RAM, regardless...

RAM is also more power hungry and expensive ....

 

[Don Y]

On 9/18/2023 12:07 PM, Lasse Langwadt Christensen wrote:

mandag den 18. september 2023 kl. 20.51.22 UTC+2 skrev Don Y:
On 9/18/2023 9:06 AM, Martin Brown wrote:
Ouch! That is a royal PITA. Mine has to have its firmware updated every now and
then if a vulnerability is found and/or exploited but it boots in under a
minute from whatever internal SSD/memory stick it has.

It issues dire warnings about not switching it off during an update.
I wouldn\'t design any new application to run out of FLASH.
If the flash was fast enough for XIP, then you\'d worry about
read wear (how do you recover if your media is \"suspect\"?)

read wear? you have a single example of a flash with a limit on reads?

It\'s not a LIMIT but, rather, a corruption of adjacent cells
caused by read activity (technically, \"read interference\" but
it\'s effects can be persistent, negating the inherent value of
a \"read only\" memory)

And, RAM tends to be faster so you\'re going to WANT to transfer
your code into RAM, regardless...

RAM is also more power hungry and expensive ....

And more versatile. The initialization code only needs to
run once and then the memory used for *it* can be used
as general purpose RAM. The FLASH in which it resides
*must* always be set aside for that code cuz you\'ve no
other place from which to get it!

 

[sci.electronics.design]

mandag den 18. september 2023 kl. 21.20.10 UTC+2 skrev Don Y:

On 9/18/2023 12:07 PM, Lasse Langwadt Christensen wrote:
mandag den 18. september 2023 kl. 20.51.22 UTC+2 skrev Don Y:
On 9/18/2023 9:06 AM, Martin Brown wrote:
Ouch! That is a royal PITA. Mine has to have its firmware updated every now and
then if a vulnerability is found and/or exploited but it boots in under a
minute from whatever internal SSD/memory stick it has.

It issues dire warnings about not switching it off during an update.
I wouldn\'t design any new application to run out of FLASH.
If the flash was fast enough for XIP, then you\'d worry about
read wear (how do you recover if your media is \"suspect\"?)

read wear? you have a single example of a flash with a limit on reads?
It\'s not a LIMIT but, rather, a corruption of adjacent cells
caused by read activity (technically, \"read interference\" but
it\'s effects can be persistent, negating the inherent value of
a \"read only\" memory)

only a potential issue when there is a mix of reads and writes

And, RAM tends to be faster so you\'re going to WANT to transfer
your code into RAM, regardless...

RAM is also more power hungry and expensive ....
And more versatile. The initialization code only needs to
run once and then the memory used for *it* can be used
as general purpose RAM. The FLASH in which it resides
*must* always be set aside for that code cuz you\'ve no
other place from which to get it!

so if the flash is fast enough the RAM is just added cost and power consumption for no benefit

 

[Don Y]

On 9/18/2023 12:30 PM, sci.electronics.design wrote:

mandag den 18. september 2023 kl. 21.20.10 UTC+2 skrev Don Y:
On 9/18/2023 12:07 PM, Lasse Langwadt Christensen wrote:
mandag den 18. september 2023 kl. 20.51.22 UTC+2 skrev Don Y:
On 9/18/2023 9:06 AM, Martin Brown wrote:
Ouch! That is a royal PITA. Mine has to have its firmware updated every now and
then if a vulnerability is found and/or exploited but it boots in under a
minute from whatever internal SSD/memory stick it has.

It issues dire warnings about not switching it off during an update.
I wouldn\'t design any new application to run out of FLASH.
If the flash was fast enough for XIP, then you\'d worry about
read wear (how do you recover if your media is \"suspect\"?)

read wear? you have a single example of a flash with a limit on reads?
It\'s not a LIMIT but, rather, a corruption of adjacent cells
caused by read activity (technically, \"read interference\" but
it\'s effects can be persistent, negating the inherent value of
a \"read only\" memory)

only a potential issue when there is a mix of reads and writes

No. *Write* disturb errors are a different kettle of fish.

And, RAM tends to be faster so you\'re going to WANT to transfer
your code into RAM, regardless...

RAM is also more power hungry and expensive ....
And more versatile. The initialization code only needs to
run once and then the memory used for *it* can be used
as general purpose RAM. The FLASH in which it resides
*must* always be set aside for that code cuz you\'ve no
other place from which to get it!

so if the flash is fast enough the RAM is just added cost and power consumption for no benefit

Flash must always be large enough to hold ALL of the code
that will EVER execute on the device. E.g., POST, BIST,
application, etc.

The flash in my devices:
- disables the field
- sets the status indicator
- runs POST to verify the CPU, FLASH, RAM and NIC are operational
- downloads the diagnostic kernel into tested memory
- downloads the BIST for the FULL device (including field)
- runs the BIST for the field
- discards the BIST and loads the run-time kernel
- loads the application code and run-time diagnostics
- unloads the initialization code after it has initialized <whatever>

A fault that arises from, e.g., a read/write disturb on the RAM
causes the device (or portions of it) to reset with all of this
code simply reloaded -- not reFLASHED.

So, the FLASH is only used once per boot. And, the total \"program
image\" can be many times larger than the SoC\'s FLASH.

 

[Martin Brown]

On 17/09/2023 20:56, Don Y wrote:

On 9/17/2023 7:37 AM, Martin Brown wrote:

Most COs (in the places I\'ve lived) have lines coming into a
room in the basement, then up to a \"wiring room\" where all of
the pairs are laid out (on punchdown blocks?).

Is a CO what we would call a cabinet? Where the main trunk line back
to the exchange is terminated and the local consumer circuits start?

Sorry.  \"Central Office\". It\'s close to what you would call an \"exchange\"
but an \"exchange\" has also historically meant the first three digits of
a (3+4) digit phone number.  Nowadays, large numbers of (copper)
circuits are handled in a CO which may span multiple \"phone number
prefixes\".

OK so our exchanges. Most here do handle one or perhaps 2 exchange codes
although ISTR you can now port your phone number.

Ah!  Well that\'s a shortsight!  I wonder how CATV and cell towers
address power issues?  The towers seem to have tiny \"support buildings\"
(if at all) barely larger than a clothes closet!

Nearby cell towers lasted about 20 hours and then stone dead. This
quickly killed the remaining mobile phones that were not switched to
airplane mode as they tried to contact more remote base stations.

That service is Digital in Name Only or \"DINO\" it combines all the
worst characteristics of VOIP (fails without power) without
eliminating the pesky final mile of ageing copper that carries the
VDSL signals.

Earlier versions (here) also had problems with acoustic modems.

Apart from Fax which is still used a lot in the NHS I don\'t think there
are much if any acoustic modems in use today.

POTS generally continues to work even when DSL is down (except if
there is a fine break small enough for RF to jump the gap
capacitively). Most importantly it still works when the mains has
failed (and for a decent length of time too - exchanges have largish
battery backup systems).

.. as long as the PHYSICAL line quality hasn\'t degraded.

Here, the CO is actually battery powered with the batteries
continuously being charged (in the event mains power fails, a
small, jet-powered genset picks up the load; in ages past,
the billing computer might not be thusly backed up so
\"free long-distance\"  :> )

Ours are battery backed up and I think mostly diesel generators although
I have seen a demo hydrogen powered one once.

A cell phone subscriber could hedge his bet by picking two
different carriers and HOPING they didn\'t share towers.

My wife and I are on different mobile networks precisely because where
we live you don\'t always have good coverage from just one.

A CATV subscriber would be entirely at the mercy of the provider
as only a single provider is allowed to operate in most
areas (e.g., towns)

In Belgium we found the CATV and internet was more reliable than the
local mains. You just needed a UPS to keep on working.

are a bit unusual in that our lines are archaic \"Exchange Only\"
lines with no cabinet between us and the exchange.

So, any line repair/reconfiguration is done AT the CO?

There is no CO the lines run right back to the exchange.

my CO = your exchange so, yes, any reconfiguration would be
done back at the exchange/CO.

Seeing a wiring cabinet *in* a neighborhood is a new
thing, for me.  Previously, I\'d only seen them in businesses
(PBX).

They are everywhere in the UK. Typically one per 100 or 200 houses.

That is the meaning of an exchange only line. They are a nightmare for
VDSL operation because of the crosstalk they induce inside the
exchange. The standard fix is that they install a new powered FTTC
cabinet nearby and run anyone nearby taking the VDSL service to that.

I\'ve not been *in* a CO/exchange for decades so can\'t speak to
their current practices.

But, given TPC\'s tendency to roll out different solutions to
problems, over time, I can only imagine it is a hodge-podge of
kludges (that all \"made sense\", at some time)

It is a bit of an issue in rural locations. Back when non-ferrous metal
prices were high there were people ripping out telco lines and railway
signalling lines for their scrap metal value. Basically tie it to a land
rover winch snip it some way away and go.

There\'s a large (20 sq ft) wiring cabinet at the entrance to our
subdivisions that terminates all of the pairs from the CO *to*
the pairs feeding the subscribers.  There is ALWAYS a telco
service vehicle parked nearby \"fixing\" something (I\'m guessing
200 homes in the subdivision?)

That is about the size of our entire local exchange including its
battery room.

By 20 sq ft, I meant the panel is 4x5 ft (by about a foot deep?)

I meant 20\' x 20\' building (actually its more like 20\'x30\').
City ones are two storey and 10x bigger.

--
Martin Brown

 

[Don Y]

On 9/19/2023 1:38 AM, Martin Brown wrote:

On 17/09/2023 20:56, Don Y wrote:
On 9/17/2023 7:37 AM, Martin Brown wrote:

Ah!  Well that\'s a shortsight!  I wonder how CATV and cell towers
address power issues?  The towers seem to have tiny \"support buildings\"
(if at all) barely larger than a clothes closet!

Nearby cell towers lasted about 20 hours and then stone dead. This quickly
killed the remaining mobile phones that were not switched to airplane mode as
they tried to contact more remote base stations.

Worth knowing. I\'ve not been \"up close and personal\" with any of the
cell towers -- but they don\'t look to have much supporting infrastructure
nearby.

That service is Digital in Name Only or \"DINO\" it combines all the worst
characteristics of VOIP (fails without power) without eliminating the pesky
final mile of ageing copper that carries the VDSL signals.

Earlier versions (here) also had problems with acoustic modems.

Apart from Fax which is still used a lot in the NHS I don\'t think there are
much if any acoustic modems in use today.

When I moved here, I used to run PEP to the local ISP. But,
that predated DSL and was fast, for the time.

Now, I may move 20GB of traffic in a day -- EVERY day -- without
batting an eyelash!

A cell phone subscriber could hedge his bet by picking two
different carriers and HOPING they didn\'t share towers.

My wife and I are on different mobile networks precisely because where we live
you don\'t always have good coverage from just one.

Here, I think towers are often shared among providers (sometimes
the same kit; other times, different kit on the same physical
structures).

And, lots of MVNAs so you know they\'re essentially parasites...

A CATV subscriber would be entirely at the mercy of the provider
as only a single provider is allowed to operate in most
areas (e.g., towns)

In Belgium we found the CATV and internet was more reliable than the local
mains. You just needed a UPS to keep on working.

I hear horror stories of CATV customers railing against the company
over service quality issues. But, we aren\'t big \"video\" consumers
(beyond movies from library, etc.) so we\'ve never subscribed.

Of course, that\'s probably true of most \"services\"; they are accommodating
for \"new subscribers\".... then switch you over to \"current subscriber\"
SUPPORT staff (usually far less attentive and friendly!)

are a bit unusual in that our lines are archaic \"Exchange Only\" lines with
no cabinet between us and the exchange.

So, any line repair/reconfiguration is done AT the CO?

There is no CO the lines run right back to the exchange.

my CO = your exchange so, yes, any reconfiguration would be
done back at the exchange/CO.

Seeing a wiring cabinet *in* a neighborhood is a new
thing, for me.  Previously, I\'d only seen them in businesses
(PBX).

They are everywhere in the UK. Typically one per 100 or 200 houses.

Growing up was rural like your example so no real *place* for them.
No \"planned subdivisions\", etc.

I went to school in Boston and wandering around looking for
phone cabinets wasn\'t high on the list of \"fun activities\"!
My exposure, there, was within the school -- where it seemed
entirely logical that the 50 dorm rooms in this building should
have ALL of their telco wiring in one spot, etc.

That is the meaning of an exchange only line. They are a nightmare for VDSL
operation because of the crosstalk they induce inside the exchange. The
standard fix is that they install a new powered FTTC cabinet nearby and run
anyone nearby taking the VDSL service to that.

I\'ve not been *in* a CO/exchange for decades so can\'t speak to
their current practices.

But, given TPC\'s tendency to roll out different solutions to
problems, over time, I can only imagine it is a hodge-podge of
kludges (that all \"made sense\", at some time)

It is a bit of an issue in rural locations. Back when non-ferrous metal prices
were high there were people ripping out telco lines and railway signalling
lines for their scrap metal value. Basically tie it to a land rover winch snip
it some way away and go.

Here, it was the copper pipes on HVAC systems. Businesses would
open their doors to discover their (roof mounted) HVAC system
had been cannabilized, overnight. Not fun when your employees
don\'t have air conditioning (required for ~9 months of the year...
we turned ours on in February, this year and it\'s still 100F
in mid September...) and the \"fix\" is likely going to require
air-freighting in a new compressor...

 

[Les Cargill]

Martin Brown wrote:

On 12/09/2023 17:57, John Larkin wrote:
On Tue, 12 Sep 2023 15:33:31 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 12/09/2023 15:18, John Larkin wrote:

This seems to be a trend, much faster internet than we signed up for,
same price. The backbone fibers must be moving petabits.

I\'m surprised that they upgrade you 10x for free. In the UK they
invariably try to extract extra money out of you for such speed upgrades
which means a lot of people are still on rather slow legacy speeds.

Likewise with phone contracts they try to extract constant or ever
increasing amounts of money from you by increasing mobile data.

It seems like suppliers here are upgrading for free to keep up with
competition. We could use cable, a microwave dish, or a couple sources
for Gbit fiber.

That seems very socialist. It surely makes more sense for them to
extract at least some additional income for increasing your speed. UK
telcos are considerably more mercenary about upgrading their customers.

They\'re hardly telcos in the US any longer. The increases in bandwidth
happen as vendors improve switching gear and they can\'t very well
throttle it.

Some of it is a side effect of cell phones and trying to offer 5G to the
home.

The interface between buyers and sellers is bizarre and they keep
getting faster almost on autopilot.

We had an AT&T internet connection over the traditional phone twisted
pairs, but it was slow and expensive and died when it rained. Comcast
threw in POTS telephone service for free when we got their internet
service. I unplugged the phones because all the calls were spam.

I presume the POTS phone service is actually a POTS connector on an all
digital VOIP service offered over their backhaul.

Yep. It\'s VoIP to a hybrid copper pair. Works well.

This is causing a lot
of trouble in the UK with BT rolling out \"Digital Voice\" over an
unwilling population of mostly elderly people who depend on features of
copper based POTS for living independently. Notably that POTS phones
still work if the mains fails and various alarms and care on call
services will only work correctly with a true copper physical line.

Cell usually works even if the local grid is down. There are panic
button services.

ADSL in its various forms shouldn\'t be that unstable unless there is
something fundamentally wrong with the local wiring (as there is in my
village - no-one past me gets more than 2Mbps ADSL on copper).

There\'s always something wrong with the local wiring, especially after
that stopped being a thing.

However since I now have a fibre connection I don\'t care. The failing
junction box (think black plastic policeman\'s helmet with multicoloured
wire knitting and joints inside) is buried in the verge in front of my
house. If the water table rises it floods and shorts out circuits. When
the guys come to sort it out it sounds like maracas when they shake it!

In theory I think it is supposed to be water tight but in practice
rodents do for the catches or seals and after a few years it isn\'t.

Strange; we found containers ( not sheet metal, something thicker -
called \'em Bud boxes ) with O-ring seals and sealed connectors for a
pretty reasonable price retail years ago. Like tens of dollars.

They seem rat-proof to me.

--
Les Cargill

 

[Les Cargill]

Martin Brown wrote:

On 16/09/2023 12:19, John Larkin wrote:
On Sat, 16 Sep 2023 11:51:56 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:


I haven\'t been able to find a picture of our underground configuration
(it is quite rare now) but this one of a normal passive BT cabinet isn\'t
too dissimilar if you image no supporting structure and the whole lot of
multicoloured knitting stuffed randomly into a double width manhole.

https://www.reddit.com/r/cablegore/comments/333ek9/inside_a_bt_telephone_cabinet/


That example is a textbook layout neat one. Ours looks like that one
after you have put a fork into it and and turned it over a few times!

I collect pictures of disgusting wiring.

https://www.dropbox.com/scl/fo/rdbz4ayuw0w60ch1f4dot/h?rlkey=k14c22nkj1leclay7itlpk28z&dl=0


It seems to me a miracle that telecoms stuff actually works!

No miracle. It\'s the watchdog timers

--
Les Cargill