On Tue, 11 Aug 2009 03:28:14 +0100, in uk.d-i-y John Rumm
wrote:
Phil Addison wrote:
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
Perhaps worth mentioning that this one is totally passive, whereas more
complex ones would (presumeably?) have some computing power at
intermediate hubs.
Well the cabling system is passive in most cases. You could perhaps lump
the switches / routers / gateways etc in with it. Other than
sophistication of the switching gear (larger setups may use "managed"
switches rather than dumb ones typical of home use) its much the same.
(some of) the computing power in a corporate environment may be in
dedicated server rooms. In a home its more likely to be distributed
around in a peer to peer fashion. Having said that its equally likely
that you would place some computing resources at the hub location - like
network attached storage to act as backup or media streaming storage.
OK.
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."
Is it worth adding this rider as counter to the bits where people might
be tempted to economise and share individual twisted pairs? Especially
with gigibit becoming common.
At end of 1st "How does it work" para, should be "Each of them IS then
terminated..."
"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?
Sorry not a good choice of wording there. Each socket is independent
from the next. They group them slightly to to make keeping track of
which socket you are wiring a bit easier.
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.
Yup, spot on.
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.
One does not usually make a patch panel a source (unless using it to say
split a phone line into two). Typically the source will be the PABX or
Ethernet Switch, or broadband router etc. The proper rack mounting
versions of these usually present RJ45/RJ11 sockets to the front to make
patching to the panel simpler.
I'm probably reading too much into the term 'patch'. To me it indicates
connecting sources to destinations via patch leads, as in the original
telephone exchange where someone making a call is connected to the
receiver (although in this case the sender and receiver will sometimes
be reversed). In your photo all the patch-panel sockets appear to be
destinations, the actual patching being done between the 'patch-panel'
itself and the other equipment. In effect the 'patch-panel' is only
being used as a termination panel. Nothing wrong with that, but could do
with clarifying for newbies to the subject, like me
).
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.
Yup. Some PABX systems may use RJ45 sockets - which means ordinary
ethernet patch cables can be used for everything. The one pictured uses
RJ11. So I simply bought a number of long RJ11 to RJ11 cables and cut
them in three - adding extra connectors to make up some shorter phone
patch leads.
Then they are RJ11 to RJ45 patch leads now?
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!
Well its a bit dull, but have a look near the end in the wiring up section:
http://wiki.diyfaq.org.uk/index.php?...anelWiring.jpg
That is the group of krone type punch down connections for sub section
of six sockets. The terminal positions are colour coded for 568A and B
wiring schemes (somewhere on the back it tells you which is which in
small print!) (I have used 568B wiring there)
So the wires come into the back of the cabinet, and get terminated one
to a socket as shown here.
I can't reconcile that
http://wiki.diyfaq.org.uk/index.php?...anelWiring.jpg
photo with this
http://wiki.diyfaq.org.uk/index.php?...PatchPanel.jpg one
because the spacing between the RJ45s in the 1st is much less than the
punch-down blocks in the 2nd. Why 2 rows in the second pic, or are we
seeing the rears of two patch panels? I suppose there must be a catx
wire connecting each terminator block on the rear of a patch-panel to
its corresponding RJ45 on the front?
What other explanations / photos do you think would make it a bit clearer?
Ideally a photo of a patch panel from above showing the complete route
through from a patch (or other input) lead at the front to a loom lead
at the back, plus the bit above explainning that patching does not have
to, or doesn't usually, happen on the patch-panel itself .
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"!!
Phil