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If you are starting a network from scratch, you will probably
be using Cat5 wire for 10/100baseT (twisted pair telco-style cables
with RJ-45 eight wire `phone' connectors). If you stumble across
some old surplus 10Base2 thin ethernet (RG58 co-ax cable with BNC
connectors) it might be suitable for linking a few machines
together in a home ethernet.
The old-fashioned thick ethernet, RG5 or RG8 cable with N connectors
is really obsolete and rarely seen anymore.
See
Type of cable... for
an introductory look at cables.
Also note that the FAQ from comp.dcom.lans.ethernet has a lot
of useful information on cables and such. FTP to
rtfm.mit.edu and look in /pub/usenet-by-hierarchy/
for the FAQ for that newsgroup.
Thinnet (10Base-2) is pretty much obsolete now. It is fine for
somebody playing around with a home network and old ISA cards.
There are two main drawbacks to using thinnet. The first is that it
is limited to 10Mb/sec - 100Mb/sec requires twisted pair. The second
drawback is that if you have
a big loop of machines connected together, and some bonehead breaks
the loop by taking one cable off the side of his tee, the whole
network goes down because it sees an infinite impedance (open
circuit) instead of the required 50 ohm termination. Note that
you can remove the tee piece from the card itself without killing
the whole subnet, as long as you don't remove the cables from the
tee itself. And if you are doing a small
network of two machines, you still need the tees and the 50 ohm
terminators -- you can't just cable them together!
It is also vital that your cable have no `stubs' -- the `T'
connectors must be attached directly to the ethercards.
Twisted pair networks require active hubs,
which start around $50. You can pretty much ignore
claims that you can use your existing telephone
wiring as it is a rare installation where that turns out to be the
case.
On the other hand, all 100Mb/sec
ethernet proposals use twisted pair, and most new business
installations use twisted pair. The wiring should be listed
as Category 5. Anything less than Cat 5 is useless.
If you are only connecting two machines, it is possible to avoid
using a hub by purchasing or making a special cross-over or null
cable. But note that some cards that try to sense autonegotiation
and so on expect to be talking to a hub and not another card, and
thus may not work in this configuration.
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