DoN. Nichols wrote:
In article ,
Grant Erwin wrote:
JohnM wrote:
Can I assume I can hook comuters with various Windows OS's together with
ethernet cards and coax?
Yes.
If so, will a Win95 OS pretty well know what to
do assuming I can get the thing to recognize the hardware or is it going
to be a real pain to make work?
Yes, it will know what to do.
Unlike when trying to get an older Windows to talk to a unix
box. Unix boxen are happy to talk to each other via ethernet (they were
doing it before Windows), and earlier Windows systems (of course) came
up with a totally incompatible protocol for everything.
In Windows boxen, mostly what you can do is set up file sharing,
where one system has the big disks, and others use the same information
over the net.
In Unix boxen, you not only have NSF (Network File System) (and
some earlier versions, such as RFS (Remote File System), but you also
have the ability to log into one system from the other, and use it just
as though you were using your local system. You can use rsh/rlogin (and
rcp for copying files), or if you are worried about security, you can
disable those, and use ssh/slogin and scp, which do everything in an
encrypted mode, so people can't snoop passwords from the net. (And yes,
it is dead easy to do. :-)
What sort of cable do these cards need? The same a TV uses by any chance?
No. TV cable will *not* work with great certainty. TV cable is coaxial cable,
which has 2 conductors. Ethernet cable has 4 conductors (2 of which are actually
used).
Not quite right.
1) Ethernet can have one of three formats (excluding fiber optic
or wireless links)
a) The really old 10Base5 -- also called "thicknet". This
is a coax almost the size of your thumb, triple
shielded, and only works with transceivers connected to
the AUI port (15-pin D connector) on some ethernet
cards. You need to have a 50-ohm terminator at each end
of the cable. You can connect transceivers in the
middle with more connectors (Type-N screw-together
connectors), or you can use "vampire taps" -- you drill
a hole through the insulation and shielding, and clamp
on a tap which will poke through the outer insulation to
contact the shielding, and then a sharp point will go
through the hole in the insulation and shielding, and
contact the center conductor.
This system is pretty much obsolete, and limited to 10
MB/S data transfer rates.
b) Somewhat newer, 10Base2 -- also called "thinnet". This
is also a double-shielded coax, but much smaller and
good for a somewhat shorter distance. The coax
connectors on this are BNC connectors. This will not
get quite as long a run as thicknet will do, but is a
lot easier to install. And, if you aren't near the run
length limit, you can get away with RG-58 cable (50 ohm
connections) -- but not with RG-59 (75 ohm, which is
used for TV connections.) (Well ... you might be able
to get away with a really short run, say six feet or
so.) But you need to have a 50 ohm terminator at each
end of the run.
This is somewhat obsolescent, and is also limited to 10
MB/S data transfer rates.
Both of the above run from end to end, and can have any number
of systems connected along the length. The following system ia
a "radial" system, where each machine has its own cable from the
computer to a hub. (Though a special cable can be made to
connect only two computers.)
c) 10BaseT/100BaseT/1000BaseT: Twisted pair ethernet.
There are *two* pairs of wires needed for this, out of
the four which the connector (RJ-45 -- like a telephone
modular connector, except that it has eight connections,
not the four of the phone (RJ-11) connector, or the six
of the RJ-13 used for phones with hold circuits.
The wires are selected in twisted pairs, and the cable
usually has four pair, though only two are used for the
ethernet. (Sometimes people use the other two for
carrying power for a wireless system.) The wires are
(counting from left to right, as the wire faces you and
the terminal blades are visible on top):
1 2 3 4 5 6 7 8
For a normal connection, the first pair goes from
pins 1 and 2 to pins 1 and 2 of the other connector, and
pins 3 and 6 go to pins 3 and 6 of the other connector.
For a computer-to-computer connection, (only two
computers, with no hub), instead you have it as follows:
Comp1 Comp2
================
1 -------- 3 \
pair 1
2 -------- 6 /
3 -------- 1 \
4 7 \
pair 2
5 8 /
6 -------- 2 /
7 4
8 5
The ones with wires between them are those which matter,
and the pin numbering is just a suggested arrangement to
coexist with the logic of the first pair.
I usually use the blue/white pair for pins 1 & 2, and
the orange/white pair for pins 3 & 5 on a four-pair
cable. (The other two pair or green/white and
brown/white.
Note that the higher the speed, the more critical the
construction and the shorter the maximum length. With
10BaseT you can get away with almost anything. With
1000BaseT, it has to be nearly perfect.
Note that a *good* crimper for RJ-45 connectors is made
by AMP, and tends to be rather expensive. The cheaper
ones are likely to not always crimp all of the blades to
the same depth, and to sometime tilt one or more so they
don't get crimped at all.
Note that the 10Base5 (thicknet) *always* has an AUI interface
between the network card an the transceiver.
The 10Base2 (thin-net) and 10BaseT (twisted pair) are more likely
to have connectors directly on the computer network card, or
built into the computer -- though transceivers for both were
made to plug into an AUI connector.
100Base2 and 1000Base2 will *only* have RJ-45 connectors on the
network cards.
Just buy network cable, stuff is dirt cheap. Don't get me wrong,
They are even available as "crossover" cables, which are what
you need to connect two (and only two) computers together.
depending on what you are doing, it is conceivable that some of your link could
be made up of coaxial cable, but actual Ethernet cards that hook directly to
coaxial cable are rare, and TV coaxial cable is the wrong impedance.
As mentioned above, it is more likely to be RG-59 (75 ohm), and
for coax ethernet, you need 50 ohm impedance (RG-58 or genuine Thin-net
cable).
And this is the wrong newsgroup. Google Tells All, in this case I suspect quite
quickly.
Perhaps so. But I think that I have covered most of what may
be needed (other than how to convince a Windows box to use that instead
of a modem to dial up a network connection. :-)
Enjoy,
DoN.
Thanks DoN, I really appreciate that (and thanks to everyone else again
too). Now that I know it's doable and the OS should help me I'll be
giving it a shot.
John
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