RE: Cat 5e Cable

["Phil Harris" <phil@xxxxxxxxxxx>]

Except they're not balanced in C-Bus...

...at the end of the day shielding on a CAT5 cable adds additional
capacitance which can be far more detrimental than induced noise (which can
be pretty easy to filter out). Add to that that most of these systems use a
pretty low speed comms protocol that isn't even what most people would
consider a slow serial link and the requirements are very different than
for
things like Ethernet.

Remember that for these distributed intelligence systems (such as C-Bus)
the
actual messaging overhead is very low and basically consists of messages of
maybe 5 or 6 bytes tops so even something like a 9,600 baud comms network
would be able to handle many hundreds of switching operations per second...

Phil

> -----Original Message-----
> From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf
> Of Gareth Cook
> Sent: 16 January 2008 21:03
> To: ukha_d@xxxxxxx
> Subject: Fw: [ukha_d] Cat 5e Cable
>
> I think this is where Keith will suggest the pairs are balanced and
> dont
> need to be shielded ?
>
>
>
>  Gareth Cook
>  IT Architect / Project Manager, SWG Sales Europe
>  Office: +44 (0)1784 445166 - Mobile: +44 (0)7980 445166
>  email: g@xxxxxxx
>
>
> ----- Forwarded by Gareth Cook/UK/IBM on 16/01/2008 21:02 -----
>
> Discussion
> Main Topic
>
> ukha_d@xxxxxxx
> Today 20:41
>
> .
> Subject:
> .
> RE: [ukha_d] Cat 5e Cable
> .
> Category:
>
>
>
> Thanks Gareth, that makes sense but surly if the cable is near mains
> voltages it still would need to be screened? Or is the screening
itself
> a
> hazard?
>
>
>
> B.
>
>
>
>   _____
>
> From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf
> Of
> Gareth Cook
> Sent: 16 January 2008 20:31
> To: ukha_d@xxxxxxx
> Subject: Fw: [ukha_d] Cat 5e Cable
>
>
>
> Its because the cbus data cables enter areas of high voltage - ie the
> DIN
> units.
>
> The sheath is 240v rated so if things do touch, the wire doesnt
because
> a
> big fire hazard.
>
> Shielded will protect you from radio frequencies, not a massive surge
> in
> voltage
>
> G.
>
> Gareth Cook
> IT Architect / Project Manager, SWG Sales Europe
> Office: +44 (0)1784 445166 - Mobile: +44 (0)7980 445166
> email: g@xxxxxxx <mailto:g%40uk.ibm.com>
>
> ----- Forwarded by Gareth Cook/UK/IBM on 16/01/2008 20:29 -----
>
> Discussion
> Main Topic
>
> ukha_d@yahoogroups. <mailto:ukha_d%40yahoogroups.com>
com
> Today 20:05
>
> .
> Subject:
> .
> [ukha_d] Cat 5e Cable
> .
> Category:
>
> Hi all,
>
> When installing cable for Idratek it is recommended to use STP
> (Shielded
> Twisted Pair). But when reading some of the excellent BLOG's one user
> used
> mains rated cable from the C-Bus website.
>
> The STP makes sense but I do not know why use mains rated cable apart
> from
> being near mains cables at times, surly you still need to use STP?
>
> Can someone explain please?
>
> B.
>
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