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<DIV><FONT size=2 face=Arial>Hi Dave </FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Wiring the rooms with multiple Cat 5 cabling
is an excellent and very practical way to provide for flexible
connections between rooms. Cat 5 cable is very well suited to handling computer
networking (of course), balanced audio, balanced video, digital audio, MIDI,
security video and power, USB extension, telephone (inc ISDN and broadband),
remote keyboard/screen control and numerous random control
signals.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>However, note I said 'balanced' audio and video.
You are probably well used to using balanced audio signals and they are
perfectly suited to Cat 5 over extended distances, using twisted pair of
unshielded or lightly shielded cabling. However, standard video signals are
'unbalanced' and designed for single-core cables with heaving coaxial screening,
and will not travel successfully in that form on Cat5 cable. To
run them over twisted pair cable such as Cat5, you need to use little
balancing/unbalancing transformers at either end - known by the shorthand of
'Baluns'.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>These used to be very expensive, but quite good
performance ones are now widely available at around £50/pair for composite
video, and will send a clean signal typically at least 50m on Cat-5. Longer runs
may need active amplifiers and 'equalization' to minimize ghosting and loss of
definition, but with good equipment and good transformers it's not always needed
even for a few hundred metres.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>One cat 5 cable has 4 twisted pairs and can carry
composite video and two stereo channels down one cable, with a pair spare. But
if you are running them all down one cable for much distance it's extra
important to get well-matched baluns and use full spec Cat-5 cable to minimize
the risks of crosstalk, which would lead to 'video buzz' on the audio. If this
is a problem or serious concern, it can be minimized by using shielded twisted
pair (Cat 5 STP) for extra shielding and run video and audio on separate Cat5
cables.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>This is assuming you are using composite video -
where al colour and luminance is combined into a single composite video signal.
Things are a bit more complex if your equipment and quality demands the use of
'component RGB' where the red, green and blue (and possibly 'syncs') need to
travel on separate pairs. In that case, for starters you need 3 or 4 baluns at
each end (multiple baluns are available for the purpose in one box), but you
also need to ensure matched timings between the signals, andt his can be more
tricky. In particular, you need to stay away from Cat-6//7 cabling as the
tecniques these use to boost digital throughput an dminimize crosstalk
cause delay differences between different pairs. For high-quality
work, expensive line drivers are used which include equalizers and pahse shifts
to compensate for cable delays.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>If you are getting to that level of work you almost
certainly need to call in a prefessional expert, but for standard audio and
composite video I would just arm yourself with a pile of decent baluns form
areputable supplier and give it a go (or experiment first with really cheap ones
from eBay in case you find that's all you need - you'll find ones meant for CCTV
cameras for under a tenner a pair!).</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>There are loads of suppliers of comercial quality
baluns, including:</FONT></DIV>
<DIV><FONT size=2 face=Arial><A
href="http://www.cyberselect.co.uk/product/438">http://www.cyberselect.co.uk/product/438</A></FONT></DIV>
<DIV><FONT size=2 face=Arial><A
href="http://www.nexxia.co.uk/Audio_Connectors/Cat5_audio_video_baluns.htm?gclid=COnU6vie_p8CFZAA4wodgkdNkQ">http://www.nexxia.co.uk/Audio_Connectors/Cat5_audio_video_baluns.htm?gclid=COnU6vie_p8CFZAA4wodgkdNkQ</A></FONT></DIV>
<DIV><FONT size=2 face=Arial><A
href="http://www.lindy.co.uk/cctv-video-balun-cat5e-6-extender-1-x-bnc-to-2-pin-connector-2-pack/32533.html">http://www.lindy.co.uk/cctv-video-balun-cat5e-6-extender-1-x-bnc-to-2-pin-connector-2-pack/32533.html</A></FONT></DIV>
<DIV><FONT size=2 face=Arial><A
href="http://www.blackbox.co.uk/products/display.asp?id=0&doc=ic443a-r2&tx=7&sx=3">http://www.blackbox.co.uk/products/display.asp?id=0&doc=ic443a-r2&tx=7&sx=3</A></FONT></DIV>
<DIV><FONT size=2 face=Arial><A
href="http://www.betterbox.co.uk/acatalog/Product_List__VGA_RGB_Component_Video_Baluns_552.html">http://www.betterbox.co.uk/acatalog/Product_List__VGA_RGB_Component_Video_Baluns_552.html</A></FONT></DIV>
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