>From Wayne Pollock:
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Cat 5e cable is UTP with 4 pairs and can support 250 MHz.
It has 48+ twists per foot which reduce crosstalk to
acceptable levels at 100 Mbps up to the 90 meter standard
maximum cable length.
When adding connectors you must not untwist more than
1/2 inch of cable at each end, and strip no more than
1 inch of insulation. Note that even one inch of
untwisted wires can reduce throughput to less than
30 Mbps! Each coupler you use requires two additional
connectors, with about 1/2" untwisted cable per
connector. Your 100MB network might be reduced to
around 15 Mbps with four connectors (1 coupler plus
the two ends). Don't even think about using 2 couplers!
The couplers themselves are straight through wires, and
I've never seen one rated higher than 10 Mbps.
Finally, while it is possible to violate standards by
using longer cables, the 100 meter limit per segment
still applies. It takes time for electricity to
propagate through a wire, and Ethernet devices will
only wait so long before assuming the segment isn't
in use and begin transmission of their own. Remember
you're using a shared media with Ethernet, so a too
long segment will result in intermittent dropped
packets. (Of course using full duplex, switched
Ethernet may mitigate that and allow longer segments.)
-Wayne
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