[ale] cat 5

[Irv Mullins]

On Monday 14 January 2002 04:04 pm, Adrin wrote:

> On a 10 BaseT wire connection you are using only 2 twisted pairs,( 4
> wires). The other four are not used. I think there is also a number of
> twist per a inch standard that is different than the standard for the 100
> BaseT. The twist is there to stop crossover like someone said before.  You
> can actually induce a voltage into another wire and cause false signals.
> That would explain why a ribbon cable did work like you wanted/expected.
> The 100BaseT uses 4 twisted pairs, ( all eight wires).  So you don't have
> room to run anything else.  If it was as simple as tipping into the wires
> to share a wiring route I wouldn't see a problem as long as the systems are
> not active at the same time. Chances are though that the cards have
> terminating resistors and these will mess with you if the signal is going
> by them. There will be a dip or drop in voltage were you tapped into the
> wire.
...

Actually, 10 baseT and 100 baseT both run on 4 wires (2 pair).
100 base T4 uses 4 pairs, but it can run on CAT 3 wiring. 
See:
http://support.3com.com/infodeli/tools/hubs/suprstac/ss100/ssii100/appa.htm

And you most definately do not want to "tap into the wire". That's a sure way 
to prevent it from working at all. (No splices, anywhere, please).

Regards,
Irv

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