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Default I want to know about bad phone wiring!

First off - I reckon there is no better place than this to get honest
descriptions of what kind of poor-quality phone wiring installations
there are around the country than asking about it here!

Second off - I need to be upfront and say this is about my day job -
and not diy phone wiring.

Basically, I'm going to be testing some prototype high speed (200Mbps)
modems, and as well as test rigs that match up to standard modern
practice - I also want to build a rig that reflects poor but all-too-
common wiring too.

I'm particularly thinking about Victorian blocks of flats (like London
tenements) that were never built with wiring in mind. So the phone
wiring to the flats might be drop wires bunched together, with more
and more of them added ad-hoc as more phones were connected.

Even more so if the ad-hoc wiring happens to be crammed together with
mains wiring (although wiring regs says in shouldn't be!)

If you can spare a couple of minutes to tell me about it (particularly
if you know the wiring layout around the building) - I'm really
interested!

The only other way I can find out is to peer around blocks of flats,
tracing wiring, making sketches and getting arrested. I'd be very
grateful if you told me about it instead!

-----------

Explanation for those that want to know what's going on:

FYI - these are high speed modems that use the existing copper wire
from your house/flat to the pole (or whatever - the place known as the
CN - convergence node), where there's another box - followed by
bonding of lines back to exchange/central office).

Hence the wiring length in original copper is usually less than 100m,
hence it can support much greater speeds - provided that it doesn't
pick up masses of electrical noise.

For those not familiar with how this stuff works - phone drop wires
consist of a number of twisted pairs - i.e. two insulated wires
twisted around each other into a spiral, before being laid next to the
others and the outer cable jacket applied. This improves the noise
immunity of the wiring because each of the wires in the pair should be
affected equally. Twisted pair wiring is then used with differential
signalling i.e. the signal is the voltage difference between the two
wires in the twisted pair. This works to a degree - if the source of
interference is too close or too big, the signal can still be
excessively affected.
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Default I want to know about bad phone wiring!

On Fri, 11 Feb 2011 06:39:00 -0800 (PST), "
wrote:


For those not familiar with how this stuff works - phone drop wires
consist of a number of twisted pairs - i.e. two insulated wires
twisted around each other into a spiral, before being laid next to the
others and the outer cable jacket applied.


Newer dropwire is like that, but the earlier stuff, much of which is
still in use, is figure-of-eight single pair construction, often of
copper-coated steel wires.
It was supposedly run from pole to house with a few twists - to
prevent it from whipping in the wind, rather than to reduce
interference.

HTH -

--
Frank Erskine
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Default I want to know about bad phone wiring!


Newer dropwire is like that, but the earlier stuff, much of which is
still in use, is figure-of-eight single pair construction, often of
copper-coated steel wires.
It was supposedly run from pole to house with a few twists - to
prevent it from whipping in the wind, rather than to reduce
interference.


Most interesting - thanks.

I'll have a google about and see if I can find more info about that.

If anyone has links to material on that, please post them up!
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Default I want to know about bad phone wiring!

wrote in message
...
First off - I reckon there is no better place than this to get honest
descriptions of what kind of poor-quality phone wiring installations
there are around the country than asking about it here!

Second off - I need to be upfront and say this is about my day job -
and not diy phone wiring.

Basically, I'm going to be testing some prototype high speed (200Mbps)
modems, and as well as test rigs that match up to standard modern
practice - I also want to build a rig that reflects poor but all-too-
common wiring too.

I'm particularly thinking about Victorian blocks of flats (like London
tenements) that were never built with wiring in mind. So the phone
wiring to the flats might be drop wires bunched together, with more
and more of them added ad-hoc as more phones were connected.

Even more so if the ad-hoc wiring happens to be crammed together with
mains wiring (although wiring regs says in shouldn't be!)

If you can spare a couple of minutes to tell me about it (particularly
if you know the wiring layout around the building) - I'm really
interested!

The only other way I can find out is to peer around blocks of flats,
tracing wiring, making sketches and getting arrested. I'd be very
grateful if you told me about it instead!

-----------

Explanation for those that want to know what's going on:

FYI - these are high speed modems that use the existing copper wire
from your house/flat to the pole (or whatever - the place known as the
CN - convergence node), where there's another box - followed by
bonding of lines back to exchange/central office).

Hence the wiring length in original copper is usually less than 100m,
hence it can support much greater speeds - provided that it doesn't
pick up masses of electrical noise.

For those not familiar with how this stuff works - phone drop wires
consist of a number of twisted pairs - i.e. two insulated wires
twisted around each other into a spiral, before being laid next to the
others and the outer cable jacket applied. This improves the noise
immunity of the wiring because each of the wires in the pair should be
affected equally. Twisted pair wiring is then used with differential
signalling i.e. the signal is the voltage difference between the two
wires in the twisted pair. This works to a degree - if the source of
interference is too close or too big, the signal can still be
excessively affected.


You would better off asking in uk.telcom or uk.telecom.broadband.

Peter Crosland


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Default I want to know about bad phone wiring!

On Feb 11, 2:39*pm, " wrote:
First off - I reckon there is no better place than this to get honest
descriptions of what kind of poor-quality phone wiring installations
there are around the country than asking about it here!

Second off - I need to be upfront and say this is about my day job -
and not diy phone wiring.

Basically, I'm going to be testing some prototype high speed (200Mbps)
modems, and as well as test rigs that match up to standard modern
practice - I also want to build a rig that reflects poor but all-too-
common wiring too.

I'm particularly thinking about Victorian blocks of flats (like London
tenements) that were never built with wiring in mind. So the phone
wiring to the flats might be drop wires bunched together, with more
and more of them added ad-hoc as more phones were connected.

Even more so if the ad-hoc wiring happens to be crammed together with
mains wiring (although wiring regs says in shouldn't be!)

If you can spare a couple of minutes to tell me about it (particularly
if you know the wiring layout around the building) - I'm really
interested!

The only other way I can find out is to peer around blocks of flats,
tracing wiring, making sketches and getting arrested. I'd be very
grateful if you told me about it instead!

-----------

Explanation for those that want to know what's going on:

FYI - these are high speed modems that use the existing copper wire
from your house/flat to the pole (or whatever - the place known as the
CN - convergence node), where there's another box - followed by
bonding of lines back to exchange/central office).

Hence the wiring length in original copper is usually less than 100m,
hence it can support much greater speeds - provided that it doesn't
pick up masses of electrical noise.

For those not familiar with how this stuff works - phone drop wires
consist of a number of twisted pairs - i.e. two insulated wires
twisted around each other into a spiral, before being laid next to the
others and the outer cable jacket applied. This improves the noise
immunity of the wiring because each of the wires in the pair should be
affected equally. Twisted pair wiring is then used with differential
signalling i.e. the signal is the voltage difference between the two
wires in the twisted pair. This works to a degree - if the source of
interference is too close or too big, the signal can still be
excessively affected.



I would think you'd encounter all you've described, plus a great deal
of untwisted pair, plus bad connections, plus long extensions with
their capacitance and a few old fashioned inductive bells and wiring
run next to bell circuits.

I hope you're including plenty of fallback modes, reduction in
throughput is far less likely to cause contract end or dispute.
Failure to implement such fallback modes is a real headache for some
people, and ties up a lot of manhours and creates ill will.


NT


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Default I want to know about bad phone wiring!

On Fri, 11 Feb 2011 06:39:00 -0800 (PST), "
wrote:


If you can spare a couple of minutes to tell me about it (particularly
if you know the wiring layout around the building) - I'm really
interested!


As has been mentioned - Some BT dropwire is figure of 8 and nailed to
walls which can get very wet so at RF the characteristics are very
variable.. The most common wiring problem though is not found just
in old houses but equally in new ones and it is where the electrician
has been given the task of doing the internal phone wiring as well as
the alarm wiring. Quite frequently they simply use alarm cable for
both the alarm system and the telephone wiring. Alarm cable isn't
twisted pair and unused cores (it is usually 6 or 8 core) are usually
simply left to act as aerials. I've seen a set of 20 new flats with
telephones wired with alarm cable.

Very long extension cables made of flat parallel laid cable are also
common -often used because they can hide under carpets. The spare
cable will be wound in a neat coil at one end!
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Default I want to know about bad phone wiring!

On Feb 11, 4:05*pm, "Peter Crosland" wrote:
wrote in message

...



First off - I reckon there is no better place than this to get honest
descriptions of what kind of poor-quality phone wiring installations
there are around the country than asking about it here!


Second off - I need to be upfront and say this is about my day job -
and not diy phone wiring.


Basically, I'm going to be testing some prototype high speed (200Mbps)
modems, and as well as test rigs that match up to standard modern
practice - I also want to build a rig that reflects poor but all-too-
common wiring too.


I'm particularly thinking about Victorian blocks of flats (like London
tenements) that were never built with wiring in mind. So the phone
wiring to the flats might be drop wires bunched together, with more
and more of them added ad-hoc as more phones were connected.


Even more so if the ad-hoc wiring happens to be crammed together with
mains wiring (although wiring regs says in shouldn't be!)


If you can spare a couple of minutes to tell me about it (particularly
if you know the wiring layout around the building) - I'm really
interested!


The only other way I can find out is to peer around blocks of flats,
tracing wiring, making sketches and getting arrested. I'd be very
grateful if you told me about it instead!


-----------


Explanation for those that want to know what's going on:


FYI - these are high speed modems that use the existing copper wire
from your house/flat to the pole (or whatever - the place known as the
CN - convergence node), where there's another box - followed by
bonding of lines back to exchange/central office).


Hence the wiring length in original copper is usually less than 100m,
hence it can support much greater speeds - provided that it doesn't
pick up masses of electrical noise.


For those not familiar with how this stuff works - phone drop wires
consist of a number of twisted pairs - i.e. two insulated wires
twisted around each other into a spiral, before being laid next to the
others and the outer cable jacket applied. This improves the noise
immunity of the wiring because each of the wires in the pair should be
affected equally. Twisted pair wiring is then used with differential
signalling i.e. the signal is the voltage difference between the two
wires in the twisted pair. This works to a degree - if the source of
interference is too close or too big, the signal can still be
excessively affected.


You would better off asking in uk.telcom or uk.telecom.broadband.

Peter Crosland


Good idea - I'll post there too.

Though I do also want to appeal to a large sample of people with a
"man in the street" type opinion - and it is diy'ers that seem to
uncover a lot of the OMG's!
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Default I want to know about bad phone wiring!

On Feb 11, 4:21*pm, Tabby wrote:
On Feb 11, 2:39*pm, " wrote:



First off - I reckon there is no better place than this to get honest
descriptions of what kind of poor-quality phone wiring installations
there are around the country than asking about it here!


Second off - I need to be upfront and say this is about my day job -
and not diy phone wiring.


Basically, I'm going to be testing some prototype high speed (200Mbps)
modems, and as well as test rigs that match up to standard modern
practice - I also want to build a rig that reflects poor but all-too-
common wiring too.


I'm particularly thinking about Victorian blocks of flats (like London
tenements) that were never built with wiring in mind. So the phone
wiring to the flats might be drop wires bunched together, with more
and more of them added ad-hoc as more phones were connected.


Even more so if the ad-hoc wiring happens to be crammed together with
mains wiring (although wiring regs says in shouldn't be!)


If you can spare a couple of minutes to tell me about it (particularly
if you know the wiring layout around the building) - I'm really
interested!


The only other way I can find out is to peer around blocks of flats,
tracing wiring, making sketches and getting arrested. I'd be very
grateful if you told me about it instead!


-----------


Explanation for those that want to know what's going on:


FYI - these are high speed modems that use the existing copper wire
from your house/flat to the pole (or whatever - the place known as the
CN - convergence node), where there's another box - followed by
bonding of lines back to exchange/central office).


Hence the wiring length in original copper is usually less than 100m,
hence it can support much greater speeds - provided that it doesn't
pick up masses of electrical noise.


For those not familiar with how this stuff works - phone drop wires
consist of a number of twisted pairs - i.e. two insulated wires
twisted around each other into a spiral, before being laid next to the
others and the outer cable jacket applied. This improves the noise
immunity of the wiring because each of the wires in the pair should be
affected equally. Twisted pair wiring is then used with differential
signalling i.e. the signal is the voltage difference between the two
wires in the twisted pair. This works to a degree - if the source of
interference is too close or too big, the signal can still be
excessively affected.


I would think you'd encounter all you've described, plus a great deal
of untwisted pair, plus bad connections, plus long extensions with
their capacitance and a few old fashioned inductive bells and wiring
run next to bell circuits.

I hope you're including plenty of fallback modes, reduction in
throughput is far less likely to cause contract end or dispute.
Failure to implement such fallback modes is a real headache for some
people, and ties up a lot of manhours and creates ill will.

NT


These boxes would be installed as a replacement master socket
(similar to an ISDN line termination) - so at least the downstream
effects of improvised phone-extension isn't something I have to reckon
with in testing (it provides a POTS outlet, so what the consumer does
with that is their own business).

Yes there are lots of lower-rate modes, although at this high
bandwidth, mode changes involve quite a bit of adaptive jiggery-pokery
and best avoided.
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variable.. *The most common wiring problem though is not found *just
in old houses but equally in new ones and it is where the electrician
has been given the task of doing the internal phone wiring as well as
the alarm wiring. *Quite frequently they simply use alarm cable for
both the alarm system and the telephone wiring. *


Wow - thanks for that - I knew I would get some high-quality
intelligence out of this group.

That possibility simply hadn't crossed the radar at all yet.
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Default I want to know about bad phone wiring!

Watch out for these.

http://share.ovi.com/media/Muddymike...e.10775?sort=0

http://share.ovi.com/media/Muddymike...e.10774?sort=0

My phone line came into the house through this when we moved here 6 years
ago, and I wondered why the broadband was a bit slow until I found this box
and had the incoming cable re rerouted so as not to use this and the
associated old cloth covered cable.

I left it in situ in the cupboard under the stairs as a novelty.

Mike




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On Feb 11, 6:01*pm, "MuddyMike" wrote:
Watch out for these.

http://share.ovi.com/media/Muddymike...e.10775?sort=0

http://share.ovi.com/media/Muddymike...e.10774?sort=0

My phone line came into the house through this when we moved here 6 years
ago, and I wondered why the broadband was a bit slow until I found this box
and had the incoming cable re rerouted so as not to use this and the
associated old cloth covered cable.

I left it in situ in the cupboard under the stairs as a novelty.

Mike


Arrgh - I think I remember you posting this one a few months back!

You mean it isn't good for 400MHz+?
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wrote in message
...
On Feb 11, 6:01 pm, "MuddyMike" wrote:
Watch out for these.
associated old cloth covered cable.

I left it in situ in the cupboard under the stairs as a novelty.

Mike


Arrgh - I think I remember you posting this one a few months back!

You mean it isn't good for 400MHz+?


I left a few of these in situ for the same reason. Must take a picture of
ones I have cleaned up.

http://share.ovi.com/media/Muddymike...e.10495?sort=0

Mike


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Default I want to know about bad phone wiring!

Watch out for aluminium wiring too. Our entire estate (1980s?) is done
with it. It has worse electrical properties, and is prone to joint
corrosion.

Andy
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Default I want to know about bad phone wiring!

On Feb 11, 8:31*pm, "MuddyMike" wrote:
wrote in message
news:b1a22767-84e9-464f-9224-5df1e063a__BEGIN_MASK_n#9g02mG7!__...__END_MASK_i ...
On Feb 11, 6:01 pm, "MuddyMike" wrote:
Watch out for these.
associated old cloth covered cable.


I left it in situ in the cupboard under the stairs as a novelty.


Mike


Arrgh - I think I remember you posting this one a few months back!


You mean it isn't good for 400MHz+?


I left a few of these in situ for the same reason. Must take a picture of
ones I have cleaned up.

http://share.ovi.com/media/Muddymike...e.10495?sort=0

Mike


I remember those as a kid in Rochdale!


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On Feb 11, 9:43*pm, Andy Champ wrote:
Watch out for aluminium wiring too. *Our entire estate (1980s?) is done
with it. It has worse electrical properties, and is prone to joint
corrosion.

Andy


Yeah - might be worth seeing if I can get hold of an old spool of the
stuff on ebay or something.
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Default I want to know about bad phone wiring!

On Feb 12, 3:21*am, " wrote:
On Feb 11, 9:43*pm, Andy Champ wrote:

Watch out for aluminium wiring too. *Our entire estate (1980s?) is done
with it. It has worse electrical properties, and is prone to joint
corrosion.


Andy


Yeah - might be worth seeing if I can get hold of an old spool of the
stuff on ebay or something.


the problem normally only shows up after years of service in
applications where the cable heats up (and contracts). As it expands
in the connector it squashes (deforms), so when it contracts its no
longer gas tight. Aluminium loves to oxidise, and then you have a
somewhat insulating oxide layer in the connection. Heating should
never happen with phone wiring, so it should behave itself. Probably
you could replicate the fault by heating the cable then clamping to it
quite gently, but I'm not convinced there's a need.


NT
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Default I want to know about bad phone wiring!

On Feb 11, 2:39*pm, " wrote:
First off - I reckon there is no better place than this to get honest
descriptions of what kind of poor-quality phone wiring installations
there are around the country than asking about it here!

Second off - I need to be upfront and say this is about my day job -
and not diy phone wiring.

Basically, I'm going to be testing some prototype high speed (200Mbps)
modems, and as well as test rigs that match up to standard modern
practice - I also want to build a rig that reflects poor but all-too-
common wiring too.

I'm particularly thinking about Victorian blocks of flats (like London
tenements) that were never built with wiring in mind. So the phone
wiring to the flats might be drop wires bunched together, with more
and more of them added ad-hoc as more phones were connected.

Even more so if the ad-hoc wiring happens to be crammed together with
mains wiring (although wiring regs says in shouldn't be!)

If you can spare a couple of minutes to tell me about it (particularly
if you know the wiring layout around the building) - I'm really
interested!

The only other way I can find out is to peer around blocks of flats,
tracing wiring, making sketches and getting arrested. I'd be very
grateful if you told me about it instead!

-----------

Explanation for those that want to know what's going on:

FYI - these are high speed modems that use the existing copper wire
from your house/flat to the pole (or whatever - the place known as the
CN - convergence node), where there's another box - followed by
bonding of lines back to exchange/central office).

Hence the wiring length in original copper is usually less than 100m,
hence it can support much greater speeds - provided that it doesn't
pick up masses of electrical noise.

For those not familiar with how this stuff works - phone drop wires
consist of a number of twisted pairs - i.e. two insulated wires
twisted around each other into a spiral, before being laid next to the
others and the outer cable jacket applied. This improves the noise
immunity of the wiring because each of the wires in the pair should be
affected equally. Twisted pair wiring is then used with differential
signalling i.e. the signal is the voltage difference between the two
wires in the twisted pair. This works to a degree - if the source of
interference is too close or too big, the signal can still be
excessively affected.


Thanks to all for your replies on this one - very valuable feedback,
and much appreciated.
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On Sat, 12 Feb 2011 03:04:15 -0800 (PST), Tabby wrote:

the problem normally only shows up after years of service in
applications where the cable heats up (and contracts). As it expands
in the connector it squashes (deforms), so when it contracts its no
longer gas tight. Aluminium loves to oxidise, and then you have a
somewhat insulating oxide layer in the connection.


And it becomes brittle. The ali wire in the "jelly bean" can fracture
at the IDC causing an open circuit but the insulation holds the wire
in the bean so it looks OK. The fracture can happen with very little
movement and stops POTS working, ADSL being RF can "leap the gap" but
at much reduced speed.

--
Cheers
Dave.





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