Ron Lowe wrote:

Good article.

ta.

There are a couple of things I'd be inclined to add:

1) 568B is the most common standard in use for fixed wiring, and I'd
suggest using that. The colour-coding on the back of your patch panel
there is marked up for both, that is pretty much standard.

I usually go for 568B, but I have come across some kit only marked in
one flavour or the other. Hence its probably better not to specify and
go with what matches what you have.

2) The way analog telephony is carried over structured cabling could be
expanded a bit, it's not always the case that the ring signal is
re-generated at the LAU. There are 3 different types of LAU: PABX
master, PSTN master, and Secondary. This may be worth a bit of
explanation. It may be also be worth linking to this page:

http://www.evonet.com/evonet/index.asp?Page=102

It can get quite complicated when you start dealing with digital/hybrid
phones as well... Perhaps its more accurate to say that the pin 3
"bell wire" is not usually carried over the structured cabling, but is
not always required either.

Oh, and I can't let this pass...

Lady Bracknell
An *Analog* pabx?
/Lady Bracknell

Get yerself an asterisk box, man!

I did look at the possibility, and compared to an Avaya or other similar
modern digital exchange it costs very little. However by the time you
look at the cost of a 16 port card, a PC (which to be fair I could
scrape together for nothing), and the power to run it, its quite
expensive compared to an analogue 4/16 PABX direct from Hong Kong.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Tue, 11 Aug 2009 22:20:31 +0100, John Rumm
wrote:

Phil Addison wrote:

Ahh I see. Does that mean you can't get short RJ11 to RJ11 patch leads?

Could you make them up from scratch from a length of phone cable, after
all, you must have had to crimp 4 RJ11s per 3 leads, so having 2 on
already seems a marginal benefit.

Indeed you can. I just went with what I had to hand - however I did not
cover it in detail in the article since it was not that important to the
concepts.

May be best to omit it altogether then, the bit about cutting into 3 had
me confused as you didn't say why into 3. I now realise it was because
the ones you had just happened to be 3x too long. Plus you advised
against DIYing patch leads and then did :-O

If you could "look through" from front to back you would see each socket
is tracked to a krone strip, and they alternate side to side to make
space for the strip of 8 punch down terminals which is wide than the
physical 8 way connector:

1 3 5
###### ###### ###### - krone strips on the back - odd numbers
_______________________
1 | 2 | 3 | 4 | 5 | 6 | - sockets on front

###### ###### ###### - krone strips on the back - even numbers
2 4 6

Aha, now I HAVE got it. The missing bit of know-how is that a krone
block is the same width as two RJ45 sockets so 2 krones one above the
other just fit in the space of the 2 RJ45s they serve. Just out of

http://wiki.diyfaq.org.uk/index.php?...RJ45Module.jpg

shows that quite well - you can see the outline of the RJ45 socket
clearly beside the punch down block.

I saw that first time and didn't relate it because there's nothing to
suggest the patch panel is like that, and the photo with the krones
turned through 90 degrees doesn't match it. Your ascii diagram is better
in the absence of a proper photo, possibly with a bit of text pointing
to the RJ45Module.jpg as an indication of how a pcb can be used to
connect them.

what do you mean by 'tracked'? Is it on a pcb, a film wire or
actual catx cable? Whatever it is still has to meet the catx spec.

A PCB. Again like in the module in the piccie above. The patch panel
just having a long narrow PCB.

OK

I will get another photo at some point. Alas I have not got any more
patch panels on my stock shelf, so will either have to wait, or go
unscrew one of mine from the cabinet.

mush mush heh-heh

Thanks for the additional clarification, of an already excellent article
- its taken me from "what thef' is structured cabling all about?" to "I
think I've got it"!!

Now all we need do is get to the "where can a buy one" and the job is done!

;-)

Err... there's just the little matter of needing to move furniture, lift
carpets, floorboards everywhere!! I'll have to stick with wireless, and
maybe get some homeplugs, for the time being. But least I know what I'm
missing now!

;-))

Phil

Phil Addison wrote:
On Tue, 11 Aug 2009 22:20:31 +0100, John Rumm
wrote:

Phil Addison wrote:

Ahh I see. Does that mean you can't get short RJ11 to RJ11 patch leads?
Could you make them up from scratch from a length of phone cable, after
all, you must have had to crimp 4 RJ11s per 3 leads, so having 2 on
already seems a marginal benefit.
Indeed you can. I just went with what I had to hand - however I did not
cover it in detail in the article since it was not that important to the
concepts.

May be best to omit it altogether then, the bit about cutting into 3 had
me confused as you didn't say why into 3. I now realise it was because
the ones you had just happened to be 3x too long. Plus you advised
against DIYing patch leads and then did :-O

Prolly why I did not put it in the article.

Having said that - RJ11 patches with 2 wires are very quick and easy -
rj45 with 8 is far less so by the time you have got all the wires in the
right order, and trimmed to the right length, and then all in the socket
to the right depth at the same time etc.



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In article ,
Ron Lowe writes:

2) The way analog telephony is carried over structured cabling could be
expanded a bit, it's not always the case that the ring signal is
re-generated at the LAU. There are 3 different types of LAU: PABX
master, PSTN master, and Secondary. This may be worth a bit of
explanation. It may be also be worth linking to this page:

http://www.evonet.com/evonet/index.asp?Page=102

I wouldn't even go so far as trying to pretend there are just two
standards for POTS over CAT5. We found at least 3 incompatible
LAUs at work -- it's basically each manuafcturer makes up their
own scheme, and make sure you use same manufacturer's LAUs at
both ends (which is a pain when you've ended up with 3 types
sprinkled around the site). The important thing is that the
A and B wired are on a pair, and assuming you don't want risk
of interference/crosstalk, the bell wire isn't carried over the
Cat 5 at all.

When I originally did my home structured cabling, I made a point
of putting A and B wires onto one of the pairs not used by
10/100 ethernet, so I didn't blow up any ethernet ports by
plugging in a POTS line by mistake. However, I'm not all gigabit
ethernet (uses all 4 pairs) so I just have to be more careful.

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

In article ,
(Andrew Gabriel) writes:

I wouldn't even go so far as trying to pretend there are just two
standards for POTS over CAT5. We found at least 3 incompatible
LAUs at work -- it's basically each manuafcturer makes up their
own scheme, and make sure you use same manufacturer's LAUs at
both ends (which is a pain when you've ended up with 3 types
sprinkled around the site). The important thing is that the
A and B wired are on a pair, and assuming you don't want risk
of interference/crosstalk, the bell wire isn't carried over the
Cat 5 at all.

When I originally did my home structured cabling, I made a point
of putting A and B wires onto one of the pairs not used by
10/100 ethernet, so I didn't blow up any ethernet ports by
plugging in a POTS line by mistake. However, I'm not all gigabit

s/not/now/

ethernet (uses all 4 pairs) so I just have to be more careful.

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

"Andrew Gabriel" wrote in message
.. .

When I originally did my home structured cabling, I made a point
of putting A and B wires onto one of the pairs not used by
10/100 ethernet, so I didn't blow up any ethernet ports by
plugging in a POTS line by mistake. However, I'm not all gigabit
ethernet (uses all 4 pairs) so I just have to be more careful.

No need.. Ethernet is a transformer coupled interface and there are
isolating transformers at each end of each pair.
They should be good to at least 1500V to meet the standard.
It why you can't blow old stuff up if you plug it into POE port.