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Frequently Asked Questions |
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What is a balun?
A balun is a small
transformer which converts an audio or video signal from unbalanced to
balanced and vice versa (hence the term "bal*un"). By doing so, baluns
make the necessary impedance adjustment for audio-visual signal
transmission between different wiring systems. In all fairness,
however, not all baluns are true "baluns;" the term balun has become a
synonymous with any device which transmits audio and video over
structured cabling.
Why should I use baluns?
There are several key
benefits derived from using baluns and twisted pair cabling.
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Baluns greatly extend
the transmission distance of video signals |
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Baluns allow you to send
multiple signals over a single cable |
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Twisted pair cabling
such as Cat 5 is smaller and
easier to pull and hide than traditional cable |
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Baluns help eliminate
ground loops and RF interference |
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Baluns and Cat 5
typically cost significantly less than traditional cable over long
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How do I expose the individual pairs in Cat 5
cabling?
There is no single
method when exposing the four individual pairs in twisted pair
cabling, such as Cat 5 and Cat 6; however, it does help to have a
cable stripping tool designed to strip the cable
jacket/insulation.
Begin by stripping
back the cable's outer jacket/insulation about an inch (or more
depending on whether multiple baluns will be connected to the pairs of
a single cable) so that the internal wires are exposed. Be careful not
to cut the internal wires when stripping the insulation/jacket. Eight
twisted wires and a string should now be visible; the string is
unnecessary and may be removed. These eight wires, which when combined
form four pairs, connect directly to the baluns. Typical protocol
pairs similar colors; the important thing is to verify the same
color-coded pairs are used on each end.
How do I crimp an unshielded RJ45 connector
onto Cat 5?
Crimping an RJ45
connector onto Cat 5 is a fairly straight forward task, assuming you
have the proper tools. Keep in mind that baluns require either the EIA/TIA
568A or 568B crimp pattern, which are the industry standards for
networking.
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First, strip a portion
of the insulation about 3/4" to expose the four twisted pairs.
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Next, untwist the
wires and fan them out so that they match either EIA/TIA 568A or 568B
pattern. |
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Evenly trim the wires
to about 1/2". Most RJ45 crimp tools feature a built-in wire trimmer.
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Insert the trimmed
wires into the RJ45 connector so that each wire is in its individual
slot. Verify each wire is completely inserted. |
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Finally, insert the
RJ45 connector into the crimp tool and squeeze firmly.
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Repeat the above steps
on the other end of the Cat 5 cable and verify pinout is identical on
each end. |
What is HDCP Encryption?
HDCP (high
definition content protection)
encryption was created as a deterrent for data piracy, particularly
due to the advent of all-digital interfaces such as DVI and HDMI. Most
consumer electronic devices with DVI or HDMI connectors are HDCP
compliant; however, some consumer and many professional grade DVD
players, projectors, and plasmas lack HDCP coding, thus it become
important when building a system to research your devices.
If a device without
HDCP encryption is connected to a device with HDCP encryption, the
picture will be seriously degraded. In most cases, the picture will
either be "grainy" or "snowy", or possibly output at a very low level
resolution.
When shouldn't I use baluns?
Baluns are not the
ideal solution for every application; certain environments and
applications will degrade twisted pair transmission performance. It is
crucial that you pre-qualify your application and uncover any
potential hazards.
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Balun performance may be
compromised in facilities with excessive RF interference, such as
factories with large AC motors. |
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Twisted pair
cabling, such as Cat 5, carrying an audio-visual signal should not
be run within one foot of fluorescent lights. |
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Twisted pair
cabling, such as Cat 5, carrying an audio-visual signal should not
be run for more than three feet parallel to high voltage lines.
Ideally, twisted pair cables which must cross high voltage lines
should do so at a 90 degree angle. |
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Twisted pair
cabling, such as Cat 5, carrying an audio-visual signal should not
be passively split or routed through an ethernet hub or switcher.
Cat 5 carrying an audio-visual signal may be run through a passive
patch bay as long as point-to-point connectivity is maintained.
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Data, such as
computer ethernet traffic, should not run on the same twisted pair
cable as your audio-visual signal. |
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Balun
performance may be compromised with excessive jumping and signal
conversions. Every time you convert a signal or pass through a
connector, there will be some signal loss. Try to maintain a
point-to-point connection, or if impossible, use an active product.
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Where
do I purchase shielded Cat 6?
Having problems
sourcing shielded Cat 6 cable? Intelix compiled a list
of distributors who stock shielded Cat 6 and other specialty
cables.
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