User manual

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CAT 5 cable is your friend....
Well, you’ve been in the audio business for a while now....you know all about audio connections,
balanced cables, multi-pairs, SJO, TRS this and XLR that....you can dress off a wiring harness
like nobody’s business....then, the industry throws “CAT 5” at you....! So, what exactly is
Category 5 cabling, and how do I terminate it? Category 5 cable, or “CAT 5” as it is commonly
known, is a wiring standard that became popular when computer networks moved from a “bus”
topology to a “star” or...... “every box is a home run” topology. The wire itself consists of 8
conductors, identified into 4 pairs, and although only two of these pairs are actually used, all four
are terminated. It is a UTP (Unshielded Twisted Pair) configuration, in true telco, or AT&T style.
The cable is coupled to in-line RJ-45 connectors, also a Bell/AT&T standard. Special crimping
tools are required to make the termination, and are available everywhere, as are the connectors.
Oh...and before you start designing cable plants for small cities....a single CAT 5 cable run should
not exceed 100 meters. Just like telco wire, there are stranded and solid varieties of CAT 5 cable.
This is important to know, because the RJ-45 connector is different for each type of wire. The
standard “bent tyne” style connector is intended for use with solid core wire, and the “aligned
tyne” connector is for use with standard wire. There have been errors when using incorrect
cable/connector combinations, so be careful. The "bent tyne" connector will generally work on
stranded wire by the way, but not the other way around. In general, make sure your connector
matches your cable type. If you aren’t sure, use the “bent tyne” variety. When terminating CAT 5
cable, it is important that the natural twist of each pair be carried through as close as possible to
the point of termination at the connector.
The EIA standard requires no more than 1/2 inch be left untwisted. More than 1/2 inch of
untwisted cable will affect performance at high bit rates. Although only 2 of the 4 twisted pairs
are used for Ethernet, it is important that all pairs be terminated, and that the conductors be
twisted together in pairs. The illustrations should give you the basics for getting your cables, and
your audio system up and running. Although pre-made, molded style cables are preferred, they
are usually impractical, since your cabling route, distance and locations are based on the jobsite
conditions and not your test bench. Additionally, you will need rack wiring, and bulk cable is the
preferred way to dress off a wire harness, as we all know. Since this manual is printed in
grayscale, you will not be able to see the color code of the wire. We have labeled them for your
convenience, but you should get familiar with the color schemes so they are second nature to you.
An error in the cabling of your audio network is often the primary cause of system errors,
so....take your time, learn it thoroughly and DO IT RIGHT THE FIRST TIME! Although the
wiring standard used in CAT 5 cabling originates with AT&T, it is functionally different for
configuring Ethernet cabling.
The Bell System uses a series of colors to identify wire pairs. This color scheme identifies the
pair numbers, and conductor polarity, and applies to the WIRE....not the connector. It is important
to know what pairs are which, and the function of the pins on the RJ-45 connector. The colors are
BLUE, ORANGE, GREEN and BROWN for the first four pairs.