Hi all,
just thought I'd throw a few Euros in...
First, until folks in the computer world know what shielded cable means (
anything less that 40 dB is lossy insulation;-))) ), I'd stear clear of
specifying them. This is 20 years of experience talking, and shields seem to
cause more problems ( 'cause they are missinstalled ) than they fix: right Ken
J?
Second, the probability of interference ( or immunity ) from LAN wiring depends
a lot on where they are routed. If LAN wires are bundled with phone wires,
interference will result... Conducted emissions control on LANs will minimize
this. Remember, the LAN can act as a path for noise to leave the PC, it need
not be direct LAN sourced noise! Poor layout of a LAN card causes this....
Third, I've tested a bunch of LAN cards from different folks.... There is a
huge difference between vendors. Not all cards have the ability to terminate a
shield properly.
I would suggest that vendors comply with conducted limits deemed appropriate by
the power that be, without applying any form of shielding. If you disagree with
the powers that be, join the committee that develops the requiremnt in the
first place! I say this as a LAN product end user... and someone active in the
committees that write the requirements for my products.
Thanks,
Derek.
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