Due to the ever-increasing influx of computer/internet-related/wifi
gizmos into the family home over the past years I've had to bite the
bullet and reconfigure my home network, basically due to ports/hubs/wifi
being needed in places never envisaged 10 years ago.

All seems to have gone OK in that everything 'works', but am wondering
to what extent this is 'all or nothing'? Eg, I'm assuming that I've
correctly connected every wire at every ethernet socket - is that right
or is there any built-in redundancy etc?

Do I need some form of tester to check everything is OK; if so what's
available/suitable for essentially one-off use like this? I'm guessing
something cheap'n cheerful like http://cgi.ebay.co.uk/310234781132 won't
tell me anything I don't already know?

One other thing bothers me slightly... I needed to run two 4m lengths of
hard-wired cable between two sockets, and rather than buy a whole new
reel of cable I just cannibalised an old 15m patch cord I've had lying
around for years; and have since read that this was unadvisable as patch
cord is made of multi-stranded wires rather than single-strand. Was
this a complete no-no? What's the problem (as I say, it does all seem
to work OK).

Thanks
David

In article Mdz7o.75427$Y21.20224@hurricane,
Lobster writes:
Due to the ever-increasing influx of computer/internet-related/wifi
gizmos into the family home over the past years I've had to bite the
bullet and reconfigure my home network, basically due to ports/hubs/wifi
being needed in places never envisaged 10 years ago.

All seems to have gone OK in that everything 'works', but am wondering
to what extent this is 'all or nothing'? Eg, I'm assuming that I've
correctly connected every wire at every ethernet socket - is that right
or is there any built-in redundancy etc?

10 and 100Mbits/s, there's no redundancy. (Only 2 of the 4 pairs
are used, but if either is broken, it won't try the others.)
1000Mbits/s uses all 4 pairs. If one of the extra pairs is broken,
it might fall back to 100Mbits/s.

Sometimes, bad cables or connections can partly work, generating
loads of retransmits in the protocol stack and low performance.
Usually, it's so bad you quickly notice.

Do I need some form of tester to check everything is OK; if so what's
available/suitable for essentially one-off use like this? I'm guessing
something cheap'n cheerful like http://cgi.ebay.co.uk/310234781132 won't
tell me anything I don't already know?

Can be useful if something isn't working, or when you first made
up the cables. Probably of little value if everything seems to be
working.

One other thing bothers me slightly... I needed to run two 4m lengths of
hard-wired cable between two sockets, and rather than buy a whole new
reel of cable I just cannibalised an old 15m patch cord I've had lying
around for years; and have since read that this was unadvisable as patch
cord is made of multi-stranded wires rather than single-strand. Was
this a complete no-no? What's the problem (as I say, it does all seem
to work OK).

The socket IDC connectors will have been designed for solid core.
If it's working, all well and good. Probably more likely to stop
working at some point than solid core would have been.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Sun, 08 Aug 2010 15:31:24 +0100, Lobster wrote:

Do I need some form of tester to check everything is OK; if so what's
available/suitable for essentially one-off use like this? I'm guessing
something cheap'n cheerful like http://cgi.ebay.co.uk/310234781132 won't
tell me anything I don't already know?

Probably not so usefule now, but I made up a cheap and cheerful
continuity tester (which said nothing about the quality of a connection
but told me it was OK).

I used four bidirectional LEDs (OK, eight normal LEDs and four diodes)
connected to a patch lead at one end. And battery and four switches at
the other. This told me of open circuit connections as well as pair
reversals/miswirings.

As I said, cheap and cheerful. But it did catch what problems there were.



--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor

Lobster wrote:
Due to the ever-increasing influx of computer/internet-related/wifi
gizmos into the family home over the past years I've had to bite the
bullet and reconfigure my home network, basically due to ports/hubs/wifi
being needed in places never envisaged 10 years ago.

All seems to have gone OK in that everything 'works', but am wondering
to what extent this is 'all or nothing'? Eg, I'm assuming that I've
correctly connected every wire at every ethernet socket - is that right
or is there any built-in redundancy etc?

Do I need some form of tester to check everything is OK; if so what's
available/suitable for essentially one-off use like this? I'm guessing
something cheap'n cheerful like http://cgi.ebay.co.uk/310234781132 won't
tell me anything I don't already know?


In general a continuity tester that plugs into each socket and shorts
the various pairs and a LED plus battery thing that plugs in the other
end to see that continuity exists, is enough for 99% of all basic faults.


One other thing bothers me slightly... I needed to run two 4m lengths of
hard-wired cable between two sockets, and rather than buy a whole new
reel of cable I just cannibalised an old 15m patch cord I've had lying
around for years; and have since read that this was unadvisable as patch
cord is made of multi-stranded wires rather than single-strand. Was
this a complete no-no? What's the problem (as I say, it does all seem
to work OK).

Thanks
David

On 08/08/2010 18:04, The Natural Philosopher wrote:

In general a continuity tester that plugs into each socket and shorts
the various pairs and a LED plus battery thing that plugs in the other
end to see that continuity exists, is enough for 99% of all basic faults.



There is one common wiring error commonly found on DIY installs which a
continuity tester will not pick up... Split pairs. The twisted pairs
are critical to the correct operation.

A common error is to wire it like this:

pins 1+2 - pair1
pins 3+4 - pair2
pins 5+6 - pair3
pins 7+8 - pair4

This may work OK at 10Mbit, and perhaps at 100 over short runs, but will
fail miserably over any length.

The correct wiring is:

pins 1+2 - pair 1 ( usually white/orange + orange )
pins 3+6 - pair 2 ( usually white/green + green )
pins 4+5 - pair 3 ( usually blue + white/blue )
pins 7+8 - pair 4 ( usually white/brown + brown )

The actual colours of the pairs is unimportant ( electrons are
colour-blind ) but it is critical that the pairing is observed. The
wiring I have described is the most commonly used T568B.

--
Ron

On Sun, 08 Aug 2010 18:27:51 +0100, Ron Lowe wrote:

There is one common wiring error commonly found on DIY installs which a
continuity tester will not pick up... Split pairs. The twisted pairs
are critical to the correct operation.

Yes...the continuity tester I made detected split pairs, and also crossed
over pairs....and I found at least one of each!
--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor

In message Mdz7o.75427$Y21.20224@hurricane, Lobster
writes
I'm guessing something cheap'n cheerful like
http://cgi.ebay.co.uk/310234781132 won't tell me anything I don't
already know?

I bought one of these some time ago (when the postage was cheaper!) and
it has been marvellous for finding damaged cables in a friend's office.
It is cheaply made but it does the job.
For us it made it quick and simple to identify which old unlabelled
cable went where and then which had been broken by the decorators.
--
Bill

On Sun, 08 Aug 2010 18:27:51 +0100, Ron Lowe wrote:

There is one common wiring error commonly found on DIY installs which a
continuity tester will not pick up... Split pairs. The twisted pairs
are critical to the correct operation.

Yes...the continuity tester I made detected split pairs, and also crossed
over pairs....and I found at least one of each!

Your tester would have identified crossed pairs with ease,
but it must have been more sophisticated than a simple dc continuity
tester to pick up split pairs. How did it work?

--
Graham.

%Profound_observation%

On Sun, 08 Aug 2010 21:42:32 +0100, Graham. wrote:

On Sun, 08 Aug 2010 18:27:51 +0100, Ron Lowe wrote:

There is one common wiring error commonly found on DIY installs which
a continuity tester will not pick up... Split pairs. The twisted
pairs are critical to the correct operation.

Yes...the continuity tester I made detected split pairs, and also
crossed over pairs....and I found at least one of each!

Your tester would have identified crossed pairs with ease, but it must
have been more sophisticated than a simple dc continuity tester to pick
up split pairs. How did it work?

Not very sophisticated really. At one end, a patch cable into a box. Each
pair connected to two LEDs (red and green) fixed opposite ways round.

At the other end, a battery, one side connected to one side of each of
the four pairs. Other side connected to other side of corresponding pair
via a switch (four switches).

Connect the two boxes, have a helper at the other end in earshot (or on a
mobile, for an isolated part of the house). Flip each switch in turn,
getting one, two, three then all four on. Then off the same way. Green
LEDs should light in turn. Crossed pairs fail to light LED, reversed
pairs light the red LED.

At least, that's as I remember it! Haven't opened the boxes recently...



--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor

On 8 Aug, 19:50, Bill wrote:
In message Mdz7o.75427$Y21.20224@hurricane, Lobster
writes

I'm guessing something cheap'n cheerful like
http://cgi.ebay.co.uk/310234781132won't tell me anything I don't
already know?

I bought one of these some time ago (when the postage was cheaper!) and
it has been marvellous for finding damaged cables in a friend's office.
It is cheaply made but it does the job.
For us it made it quick and simple to identify which old unlabelled
cable went where and then which had been broken by the decorators.
--
Bill

Toolstation manage to knock a quid off Maplins price for walk in
convenience.

http://www.toolstation.com/shop/Elec.../sd2745/p10555

It tests each lime in sequence so split pairs show up.

Cheers
Adam

In message , Bob Eager
writes
On Sun, 08 Aug 2010 21:42:32 +0100, Graham. wrote:

On Sun, 08 Aug 2010 18:27:51 +0100, Ron Lowe wrote:

There is one common wiring error commonly found on DIY installs which
a continuity tester will not pick up... Split pairs. The twisted
pairs are critical to the correct operation.

Yes...the continuity tester I made detected split pairs, and also
crossed over pairs....and I found at least one of each!

Your tester would have identified crossed pairs with ease, but it must
have been more sophisticated than a simple dc continuity tester to pick
up split pairs. How did it work?

Not very sophisticated really. At one end, a patch cable into a box. Each
pair connected to two LEDs (red and green) fixed opposite ways round.

At the other end, a battery, one side connected to one side of each of
the four pairs. Other side connected to other side of corresponding pair
via a switch (four switches).

Connect the two boxes, have a helper at the other end in earshot (or on a
mobile, for an isolated part of the house). Flip each switch in turn,
getting one, two, three then all four on. Then off the same way. Green
LEDs should light in turn. Crossed pairs fail to light LED, reversed
pairs light the red LED.

At least, that's as I remember it! Haven't opened the boxes recently...



The device in the ebay ad sequences through the wires, so it doesn't
need the second person at the far end. I think I paid a total of either
£2.98 or £3.98 by choosing the right Chinaman.
--
Bill

On Mon, 09 Aug 2010 01:04:55 +0100, Bill wrote:

In message , Bob Eager
writes
On Sun, 08 Aug 2010 21:42:32 +0100, Graham. wrote:

On Sun, 08 Aug 2010 18:27:51 +0100, Ron Lowe wrote:

There is one common wiring error commonly found on DIY installs
which a continuity tester will not pick up... Split pairs. The
twisted pairs are critical to the correct operation.

Yes...the continuity tester I made detected split pairs, and also
crossed over pairs....and I found at least one of each!

Your tester would have identified crossed pairs with ease, but it must
have been more sophisticated than a simple dc continuity tester to
pick up split pairs. How did it work?

Not very sophisticated really. At one end, a patch cable into a box.
Each pair connected to two LEDs (red and green) fixed opposite ways
round.

At the other end, a battery, one side connected to one side of each of
the four pairs. Other side connected to other side of corresponding pair
via a switch (four switches).

Connect the two boxes, have a helper at the other end in earshot (or on
a mobile, for an isolated part of the house). Flip each switch in turn,
getting one, two, three then all four on. Then off the same way. Green
LEDs should light in turn. Crossed pairs fail to light LED, reversed
pairs light the red LED.

At least, that's as I remember it! Haven't opened the boxes recently...



The device in the ebay ad sequences through the wires, so it doesn't
need the second person at the far end. I think I paid a total of either
£2.98 or £3.98 by choosing the right Chinaman.

I made this 15 years ago...it was the cheapest solution then.

--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor

"Lobster" wrote

Do I need some form of tester to check everything is OK; if so what's
available/suitable for essentially one-off use like this? I'm guessing
something cheap'n cheerful like http://cgi.ebay.co.uk/310234781132 won't
tell me anything I don't already know?

Not sure how reliable it is, but if you have 2 1Gb enabled laptops, I would
expect the network connection to report its speed in the task bar.
Usually get something like "Local Area Network Connected at 1Gb".

Phil

"Adam Aglionby" wrote in message
...


Toolstation manage to knock a quid off Maplins price for walk in
convenience.

http://www.toolstation.com/shop/Elec.../sd2745/p10555

It tests each lime in sequence so split pairs show up.

How?
I don't see how a simple continuity tester (which is all it is) can show up
split pairs.
A split pair will still be connected at each end but by the wrong bit of
copper.

Adam Aglionby wrote:

Toolstation manage to knock a quid off Maplins price for walk in
convenience.

http://www.toolstation.com/shop/Elec.../sd2745/p10555

It tests each lime in sequence so split pairs show up.

My interpretation of a split pair is the situation where the pins at each
end are paired off correctly but not connected by wires twisted in the same
pair, e.g. pins 3+6 joined by green and blue wires instead of white/green
and green.

None of these cheap testers will detect this type of fault for which you
need expensive test kit costing a thousand pounds or more. This is only
worthwhile for anyone doing large scale testing. The best way to check for
this type of fault on a domestic setup is to rely on thorough visual
examination of the terminations.

--
Mike Clarke

Mike Clarke wrote:
Adam Aglionby wrote:

Toolstation manage to knock a quid off Maplins price for walk in
convenience.

http://www.toolstation.com/shop/Elec.../sd2745/p10555
It tests each lime in sequence so split pairs show up.

My interpretation of a split pair is the situation where the pins at each
end are paired off correctly but not connected by wires twisted in the same
pair, e.g. pins 3+6 joined by green and blue wires instead of white/green
and green.

None of these cheap testers will detect this type of fault for which you
need expensive test kit costing a thousand pounds or more. This is only
worthwhile for anyone doing large scale testing. The best way to check for
this type of fault on a domestic setup is to rely on thorough visual
examination of the terminations.

Opinion endorsed.

Actually, you get degradation at even 10Mpbs.

On 09/08/2010 10:06, Mike Clarke wrote:

None of these cheap testers will detect this type of fault for which you
need expensive test kit costing a thousand pounds or more. This is only
worthwhile for anyone doing large scale testing. The best way to check for
this type of fault on a domestic setup is to rely on thorough visual
examination of the terminations.


Correct.

No simple DC test will pick this up.
Only a fancy tester or carefull visual inspection.

Or, of course, carefull competent installation in the first place!


--
Ron

On 09/08/2010 06:51, Bob Eager wrote:
On Mon, 09 Aug 2010 01:04:55 +0100, Bill wrote:

In , Bob Eager
writes
On Sun, 08 Aug 2010 21:42:32 +0100, Graham. wrote:

On Sun, 08 Aug 2010 18:27:51 +0100, Ron Lowe wrote:

There is one common wiring error commonly found on DIY installs
which a continuity tester will not pick up... Split pairs. The
twisted pairs are critical to the correct operation.

Yes...the continuity tester I made detected split pairs, and also
crossed over pairs....and I found at least one of each!

Your tester would have identified crossed pairs with ease, but it must
have been more sophisticated than a simple dc continuity tester to
pick up split pairs. How did it work?

Not very sophisticated really. At one end, a patch cable into a box.
Each pair connected to two LEDs (red and green) fixed opposite ways
round.

At the other end, a battery, one side connected to one side of each of
the four pairs. Other side connected to other side of corresponding pair
via a switch (four switches).

Connect the two boxes, have a helper at the other end in earshot (or on
a mobile, for an isolated part of the house). Flip each switch in turn,
getting one, two, three then all four on. Then off the same way. Green
LEDs should light in turn. Crossed pairs fail to light LED, reversed
pairs light the red LED.

At least, that's as I remember it! Haven't opened the boxes recently...



The device in the ebay ad sequences through the wires, so it doesn't
need the second person at the far end. I think I paid a total of either
£2.98 or £3.98 by choosing the right Chinaman.

I made this 15 years ago...it was the cheapest solution then.


That's just a simple continuity test, surely?

So long as:
1 connects to 1,
2 to 2
3 to 3 and so forth,
it passes.

That's not good enough.

--
Ron

On 09/08/2010 09:41, dennis@home wrote:


"Adam Aglionby" wrote in message
...


Toolstation manage to knock a quid off Maplins price for walk in
convenience.

http://www.toolstation.com/shop/Elec.../sd2745/p10555


It tests each lime in sequence so split pairs show up.

How?
I don't see how a simple continuity tester (which is all it is) can show
up split pairs.
A split pair will still be connected at each end but by the wrong bit of
copper.

Correct.

--
Ron

On Mon, 09 Aug 2010 21:35:14 +0100, Ron Lowe wrote:

On 09/08/2010 10:06, Mike Clarke wrote:

None of these cheap testers will detect this type of fault for which
you need expensive test kit costing a thousand pounds or more. This is
only worthwhile for anyone doing large scale testing. The best way to
check for this type of fault on a domestic setup is to rely on thorough
visual examination of the terminations.


Correct.

No simple DC test will pick this up.
Only a fancy tester or carefull visual inspection.

Or, of course, carefull competent installation in the first place!

Yes, I appreciate that now. My homebrew tester was good enough...I would
have had to make the same mistake both ends for it not to show as a
fault. I can see a cowboy installer doing that, though!



--
Use the BIG mirror service in the UK:
http://www.mirrorservice.org

*lightning protection* - a w_tom conductor

On 09/08/2010 22:03, Bob Eager wrote:

No simple DC test will pick this up.
Only a fancy tester or carefull visual inspection.

Or, of course, carefull competent installation in the first place!

Yes, I appreciate that now. My homebrew tester was good enough...I would
have had to make the same mistake both ends for it not to show as a
fault. I can see a cowboy installer doing that, though!

Yes, my introduction to this was some years ago when I inherited a
network which had been recenty 'upgraded' from co-ax to utp. It seemed
to work OK when all the devices were 10Mbit, but the 'new' 100Mbit
devices were falling over.

The installation had been done by a well-meaning but clueless
electronics maintenance guy who had no knowledge about ethernet wiring.

A few days of re-punching-down had everything working.

--
Ron

There is one common wiring error commonly found on DIY installs which
a continuity tester will not pick up... Split pairs. The twisted
pairs are critical to the correct operation.

Yes...the continuity tester I made detected split pairs, and also
crossed over pairs....and I found at least one of each!

Your tester would have identified crossed pairs with ease, but it must
have been more sophisticated than a simple dc continuity tester to pick
up split pairs. How did it work?

Not very sophisticated really. At one end, a patch cable into a box. Each
pair connected to two LEDs (red and green) fixed opposite ways round.

At the other end, a battery, one side connected to one side of each of
the four pairs. Other side connected to other side of corresponding pair
via a switch (four switches).

Connect the two boxes, have a helper at the other end in earshot (or on a
mobile, for an isolated part of the house). Flip each switch in turn,
getting one, two, three then all four on. Then off the same way. Green
LEDs should light in turn. Crossed pairs fail to light LED, reversed
pairs light the red LED.

At least, that's as I remember it! Haven't opened the boxes recently...


Yes I have a commercial pair of units that does the same job, albeit the
switching stepping through the pairs automatically.

But take my word for it, this kind of tester will diagnose straight, crossover,
short circuit and open circuit pairs, but it will be unaware of split pairs!
After all, how could it?
The tester will see the copper conductors forming circuits exactly as expected, the only difference is what it sees as a pair of
conductors, are not mutually twisted together.
--
Graham.

%Profound_observation%

On 11 Aug, 23:02, "Graham." wrote:
There is one common wiring error commonly found on DIY installs which
a continuity tester will not pick up... *Split pairs. * The twisted
pairs are critical to the correct operation.

Yes...the continuity tester I made detected split pairs, and also
crossed over pairs....and I found at least one of each!

Your tester would have identified crossed pairs with ease, but it must
have been more sophisticated than a simple dc continuity tester to pick
up split pairs. How did it work?

Not very sophisticated really. At one end, a patch cable into a box. Each
pair connected to two LEDs (red and green) fixed opposite ways round.

At the other end, a battery, one side connected to one side of each of
the four pairs. Other side connected to other side of corresponding pair
via a switch (four switches).

Connect the two boxes, have a helper at the other end in earshot (or on a
mobile, for an isolated part of the house). Flip each switch in turn,
getting one, two, three then all four on. Then off the same way. Green
LEDs should light in turn. Crossed pairs fail to light LED, reversed
pairs light the red LED.

At least, that's as I remember it! Haven't opened the boxes recently...

Yes I have a commercial pair of units that does the same job, albeit the
switching stepping through the pairs automatically.

But take my word for it, this kind of tester will diagnose straight, crossover,
short circuit and open circuit pairs, but it will be unaware of split pairs!
After all, how could it?
The tester will see the copper conductors forming circuits exactly as expected, the only difference is what it sees as a pair of
conductors, are not mutually twisted together.
--
Graham.

%Profound_observation%

Yup guys, I now got the difference between split pairs and any other
wiring anomaly ;-)

Backing what Ron said the importance of getting it right, from another
forum:

Historically, many buildings that had no problems started to see noise issues when they installed early electronic fluorescent ballasts. Switching computer power supplies caused similar problems. T1's happily ran alongside phone wires for decades until DSL came along.

Today, we're seeing a profusion of powerline communication schemes,
each with it's own set of interference issues.

Fluke does a nice network multimeter with basic TDR at just under a
grand, hey the prices are coming down.

Cheers
Adam

In message , "dennis@home"
writes
How?
I don't see how a simple continuity tester (which is all it is) can
show up split pairs.
A split pair will still be connected at each end but by the wrong bit
of copper.
It will show them if the installer hasn't made the same mistake at each
end but if they have then you're sunk...
--
Clint Sharp