Re: Video over CAT5

[Keith Doxey <keith.doxey@xxxxxxx>]

On Thursday, November 05, 1998 2:27 PM, Nigel Orr [SMTP:nigel.orr@xxxxxxx]
wrote:
> >Applied Technologies Manufacturing Ltd
>
>
> That's all of about a mile from my house!  Thanks for the info- must
pop
> round and have a word with them ;-)
>
> >As to distributing Video over CAT5......I currently have
prototypes
> >in use of units sending
> >1.	Composite Video, Stereo Audio and IR data
> >2.	SVGA
>
> How much circuitry does the composite video take?  Is it just an
impedance
> match, or do you need more power for drivers etc?  I'd only be sending
it
> down a short length (maybe up to 10m of cat-5), with audio on the
other
> pairs (possibly IR at a later date, but it would probably be on
another
> cable)- is that likely to work straight off down the cable?
>
>

Hi Nigel,

The circuitry is all active electronics sending balanced signals down the
CAT5
Power consumption is only a few milliamps....havent measured it yet!!!
Cost of parts is under 15UKP for a Tx/Rx pair for AV use and under 40UKP
for the SVGA version based on a 1 off price. If I was to buy the parts at
100off
prices the total cost would plummet.
Balanced signals allow unscreened cable and freedom from earth loops, both
of which will be problems sending unbalanced signals down CAT5.
A video switcher that I built and installed in a pub 4 years ago is giving
excellent
pictures sending over ordinary "4 core individually screened"
cable
(Maplin  "Cable Quad" XR23A) at distances of upto 25 metres.
There are 16 cables
running adjacent to each other and there are Neon signs less than 1 metre
away.
there is no interference whatsoever but it is impossible to send more than
1 video
signal on each cable as they interfere with each other. That problem does
not exist
with balanced CAT5.

Mark McCall saw the first prototype back in January when I visited him.

Keith

Keith Doxey
http://www.btinternet.com/~krazy.keith
Krazy Keith's World of DIY Home Automation

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