On 2010-05-03, pyotr filipivich wrote:
Larry Jaques on Mon, 03 May 2010 06:50:26
-0700 typed in rec.crafts.metalworking the following:
[ ... ]
Question: Why did the idiot put the keyboard legs on the wrong side?
The -front- should be lifted to alleviate carpal stress, not the back.
"It made sense, at the time." A universal answer which explains
many decisions, particularly when years later the person being asked
has no idea why the decision was made that way in the first place.
I have a network cable, but apparently one cannot simply plug it
into the two ports on computers and make a simple home network.
You can with a crossover cable. The twisted pair ethernet uses
two pair out of the four (8 wires) available on the RJ-45 modular
connector. One pair is transmit and the other pair is receive. If you
use a standard cable, it is the equivalent of each computer shouting
into the other computer's mouth, and listening to the other computer's
ear. Not very good for communication.
Ethernet hubs listen and talk on the opposite pair, so you use a
straight through cable for talking to them.
Since the same connector is used for a lot of other functions,
the pinout is not as simple as you may expect. If you hold the
connector with the wire towards you and the connector blades facing up,
and number from left to right, you use the following pairs:
1\______ first pair
2/
3\
4 \______Second pair
5 /
6/
7
8
That is 1 & 2 for the first pair, and 3 & 6 for the second pair. Other uses
for the plug use different combinations of wires. When used for a
phone, the talk circuit is on pins 4 & 5 and other pins are used for
things usually needed only for a phone with a hold circuit.
Other network uses for the same connector include the T1, and the Frame
Relay (which use other pairs of pins.
In the cable, 1 & 2 are twisted together (pair 1)
3 & 6 are twisted together (pair 2)
4 & 5 are twisted together (pair 3)
7 & 8 are twisted together (pair 4)
To make the crossover cable:
end 1 end 2
1---------------3
2---------------4
3---------------1
6---------------2
The other four pins at each end can be left open, or crossed over as you
wish.
Now
_that_ is dumb. I'm updating the Sneakernet protocols to work with a
thumb drive. "Windows - it just works."
Now -- if you have a router, it will probably do DHCP and
automatically assign IP addresses to the two computers. If you have
just a plain hub or a switch, or a crossover cable as described above,
you will have to go into both comptuers' network configuration programs
and allocate different IP addresses to the two ends. Ideally, you want
to pick IP addresses which will not be used on the outside net. There
are several groupings, but the one which gives you the most leeway to
expand is the one which starts with "10.". There are four "octets",
separated by '.'s. Ideally, pick the first three to be the same at both
ends, and you can then just worry about picking different numbers for
the last octet. The range of legal values of the octets are between 0
and 255, but for some reasons it will be good to avoid 0, and 255 for
the last octet. By making only the last octet different, you don't have
to worry about things like the netmask to allow the computers to talk to
each other.
The reason that this is so complex is because it was designed
not just to connect two computers together, but rather millions of
computers around the world.
But you *can* make two Windows boxen talk to each other if
you know how to configure it, and have (or make) either a crossover
cable, or have a hub or router.
I can tell you how to do it with unix boxen, but I don't play
with Windows often enough to remember how to do it. Search on the web.
You can probably pick up a used DSL modem or wireless hub or
something similar and they will handle the DHCP for you, even if you
don't have anything connected to the outside world. (Be careful with
the wireless hub, because it will result in others driving by your house
(or the nearby neighbors) being able to pick up your communications,
even if you are not connected to the outside net.
Enjoy,
DoN.
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