News Group Posts

CAT5 wiring

From: "Vania Lolham" <vlolham@nsw.bigpond.net.au>
Newsgroups: comp.unix.sco.misc
Subject: Re: Hubs
Date: Fri, 23 Jul 1999 01:32:19 +1000
Message-ID: <7n7dbt$eg5$1@m2.c2.telstra-mm.net.au> 
References: <01bed2cc$1ed21b80$0101a8c0@transova> 
X-MSMail-Priority: Normal
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Hi,

You are right about the twist difference in all 4 pairs.
I was called out to many sites big or small from 5 user
to 500 use with the problems most of you facing now!

Example: you or your client started with co-ax cable BNC connector 4 to 10 Mbps depend on who done the cabling and quality of the NIC's and it was fine then.  And as your business grow, your cable length grows too, till you reach your 185meter limit and accordingly more traffic in the cable and resulting in a lot of data collision, packet loss and holts.

You or your client will take the plunge and change to
10base-T, using patch panels and hubs.  At this point the
cable guy is the key to achieve the best performance or
a nightmare.  Most cable guys didn't know anything about
category 1,2,3,4,5 now 6. and run the cables from one side
of the office to the other and over the power cables and
light fittings and bend and twist and squeeze the cable.
End result was okay, the improvement over Co-Ax was 50%
better, and everyone was happy.

Until the client decided to go super highway with 100Mbps and
intelligent Auto Sense hubs.

This is where someone will get fired. the bloody hub turned
in to a Christmas tree!, signals keep jumping up and down
flashing from 10 to 100 and data collision light flashing
and so on.

WHY? the answer is not knowing how to design a bullet proof
network from the start to allow growth.

A good practice is to spend a bit more from the start on
the quality of the network cabling and accessories than
finding yourself in a situation that you
have to Re-Do-It all over again.

Now this is my advise to you.
-------------------------------
Cat-5 Cabling terminology : each pair has a full colour
wire twisted with another of the same colour with stripe
or just white called "mate".(instead of saying "white" or
"white with colour X stripe).

Four twisted pairs are: Green-Orange-Blue-Brown
Wiring spec for T568A: pinout:(hold the plug in front of you and clip
pointing up left to write is 1 to 8)
    1-Green(Mate)
    2-Green
    3-Orange(Mate)
    4-Blue
    5-Blue(Mate)
    6-Orange
    7-Brown(Mate)
    8-Brown

Wiring spec for T568B: pinout:
    1-Orange(Mate)
    2-Orange
    3-Green(Mate)
    4-Blue
    5-Blue(Mate)
    6-Green
    7-Brown(Mate)
    8-Brown

Important Note: To achieve 100Mbps (100Mhz) you must follow these
instruction carefully.
    1- Not all Cat-5 cables are suitable for 100Mbps (choose the known
brand), but any Cat-5 will be adequate for 10Mbps.
    2- Cat-5 cable for 100Mbps or 100Mhz freq have to have IEEE standard and
FDDI networks compliant and
         each copper wire have to be 22AWG for Cat-5 and 24AWG for Cat-6,
read the compliance on the
         package or the cable's jacket.
    3- The maximum bending radius of the cable is 25.4mm without the
insulation cracking.
    4- UTP Cat-5 cable shall not cross any power cable carrying more than
60volts, minimum separation 60cm
         between the Data cable and Power cable of  low voltage.
    5- If you are making your own patch cables or terminating your patch
panel have to follow this important method:
                        1-When patching the cable, jacket should not exposed
the wire more than 6mm after termination.
                        2-When terminate each pair, do not UN-twist them
more then 4mm. major losses occurs at the
                            patch panel and workstation's
socket(wall-mount).
                        3- patch cable have to match your patch panel
sockets(read on the socket T568A or T568B)
                            and entire network have to have one type of
wiring implementation.
    6- Never run the cable near fluoro light ceiling unit ( Electro Magnetic
Interference will cause packet loss).
    7- Maximum cable length(segment) from Patch panel to workstation's NIC
is 100 meter no more(best is stay under
         90 meter from the patch panel  to the wall socket then allow 2 to 3
meter for the patch cable from wall socket to
          the NIC.
    8- use a path for all the cables going from patch panel and group them
when they have to change direction.
          follow the nature simple examples: Tree and Heart.
    9- Always use solid wire for cable run from the patch panel to the
workstation and stranded wire for the patch cable
         form patch panel to the hub and from wall socket to the computer.
    --------------
    In most cases for higher velocity and frequency stability use T568A
topology.
    But the most important of all after you did the above is matching your
Hub with the NICs, try to use one manufacturer
    or brand name for your Hubs and NICs for the right speed. Never mix and
match then.

    I hope this short course will solve most of your common problems.

    Regards
    Vania


Kyle Schuiteman <kyles@transova.com> wrote in message
news:01bed2cc$1ed21b80$0101a8c0@transova...
> Hi I have a openserver machine here with a 3com etherlink xl card in it.
>
> Here is the probelm.  I put in a new 3com superstack entry hub to replace
> an older 3com linkbuilder hub.  The server will be seen on the old hub but
> not on the new one.( I can ping the server on the old one and not on the
> new one).  What gets stranger is if I link the old hub to the new one and
> plug the server into the old hub that works too.
> I have a test machine here with same software setup etc and it connects
> just fine to the new hub.  Any ideas.  It has to be a setup issue with the
> network card.
>
> please respond vi email
> kyles@transova.com

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