On Mon, 10 Aug 2009 19:07:45 +0100, in uk.d-i-y John Rumm
wrote:
Phil Addison wrote:
On Sat, 25 Jul 2009 00:41:35 +0100, in uk.d-i-y John Rumm
wrote:
As usual, for your delectation / derision etc:
http://wiki.diyfaq.org.uk/index.php?..._wiring_system
Article much appreciated John, especially sections 1-3 that answer the
question long in my mind "what thef' is structured cabling all about?".
But any idea why its called structured? It doesn't seem to have any
structure at all, just a clever method of re-configuring, the price
being that you put in loads of wiring much of which may never be used
(at least concurrently). I always assumed 'structured' implied some kind
of hierarchy. Well, now I know, thank you!
Well there is a hierarchy - however I have only concentrated on the bit
of it that is likely to be of interest in a domestic or small commercial
setting (the so called "horizontal cabling" where a central hub fans out
to individual work locations).
More structure comes in when you start to consider backbone cabling
(i.e. cables between central hubs, and hubs / server rooms), "Entrance"
cabling - i.e. getting external services like phone and data links into
the central hubs etc. You can even consider the patch lead cabling from
fixed wall ports to equipment separately if you want (which, thinking
about it I ought to mention in the article).
Perhaps worth mentioning that this one is totally passive, whereas more
complex ones would (presumeably?) have some computing power at
intermediate hubs.
(have a look at he wikipedia article link at the end - that gives a
slightly bigger picture)
Haha... so big it needed a fish-eye lens to take it. I did spot that at
the end they say "Cabling standards demand that all eight connectors in
Cat5/5e/6 cable are connected, resisting the temptation to 'double-up'
or use one cable for both voice and data."
A couple of minor points reading through the rest of it...
How many wires/pairs are there inside a catx cable? Perhaps mention that
catx cable is what you are familiar with connecting your computer to
router/cable modem (so long as its not a USB cable modem).
In Cat5e there are 4 pairs. Of which an analogue voice channel will use
1, a 10 or 100 Mb ethernet connection will use 2, and a gigabit or
higher ethernet connection will use all 4.
In "Material (10).." definition of LAU has not yet been given. It's
found much later near the end of the article.
Ta, I will go fix...
ok, try that; a modified "how does it work" section...
At end of 1st "How does it work" para, should be "Each of them IS then
terminated..."
At the central location all of the wires are terminated at a bank of sockets
on a "patch panel". This is simply a row of sockets all joined together in a
single module.
"joined together"?... Looking at your close up photo, or better still
the close-up of close-up
, the RJ45's can be seen grouped in blocks of
6, but surely each socket is connected to a unique cable not paralleled
up, or am I missing the point?
Seems to me that each individual 'long' cable in your loom is
tetrminated at the push-down connectors on the back of one of the RJ45
sockets visible on the front of your patch panel. These RJ45s are signal
'destinations' typically connected to a wall plate in a distant room.
Other RJ45 sockets could be 'sources' with short lengths of cable
connected at the back, typically plugged in to say a nearby router or
broadband modem. There are exceptions such as an 'source' phone line
which will be a long cable running back to an incoming BT (or other)
master socket.
If I'm on the right track then, in your photo the grey cables are phone
line 'patch cords' linking your phones to the PABX at the bottom, and
the blue ones are short catx 'patch cables' linking the central network
switch to various remote computers or other network devices.
All this, or the real answer, must be obvious to those that have done
it, but I just spent 1/2 hour googling and nowhere, even
http://en.wikipedia.org/wiki/Patch_panel, could I find what wiring lies
behind the front of a patch panel!
Phil