HP & Compaq - test-drb@ccmp.vtda.org

7 Sep 2001

On Sep 7, 14:02, Mike Ford wrote:
...
  It would have
helped if the installers (before my time)
hadn't wire-tied the cat 5 runs to the nearest 110v A/C
lines... three-foot parallel runs, in fact... 
 My house is done is untwisted bellwire, any kind of cat5 sounds like
 nirvana to me.

 CAT5 is shielded twisted pairs isn't it? Why would proximity to 60 hz ac be
...
  a problem, or are the network cards just REALLY poorly
designed (rejection
...
  of common mode noise)? 
Nope, Cat 5 is UTP -- UNshielded twisted pair.  It has reasonable
common-mode rejection, but nothing is perfect.  In long runs, such as you'd
find in a typical commercial building infrastructure, you'd notice quite a
difference if the UTP was too close to power cables.  They're notoriously
noisy.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York