Why do we have cross-over cables.

situation.

logical

need

It's not really relevant anyway. Neither a token ring, now Ethernet's backoff approach, can work before it's been established which wires are which.

There may be a standard that describes the process of identifying the wires. Whether there is is what I asked.

Sylvia.

IIRC it was used in "War Games" (1983)

Not all modems provided electronic control of the "hook switch" (i forget the correct term) if you were lucky you had one that did.

Want to play a game?

there's not such thing,

derive the timimngs from the mac address

Helps if there's a standard that says how, which was my original question.

Sylvia.

Typo. Should have been obvious.

Sometimes. Sometimes not.

If you know of a standard, then why not provide a reference?

Sylvia.

You seem to have missed the point of the OP's question. You are excused because you are of an age when an RS232 or Centronics interface was normal.

As other posters have pointed out it was cheaper to manufacture straight through cables and in those days there was a clear distinction the devices at each end of a cable. Pin n of one device could reasonably be defined as a receiver and Pin n of the "other" device could be defined as a transmitter. In the last thirty years that has changed and today it is preferable to treat all devices as peers.

The OP wanted to know why the distinction between devices existed rather than _always_ connecting them with a crossover cable. It was a perfectly reasonable question and she has been provided with sensible answers by those who managed to understand it.

I don't think it requires a "standard" to identify the wires. A NIC must be able to identify a valid packet so swapping two wires until it does so is not a demanding task now that a microprocessor is incorporated on every device.

Part of the issue was to make cable testing easier for low end techs, they are pin for pin.

Yes. It is part of the IEEE 802.3 series. See:

situation.

Add some conditions. There is an orderly passing sequence. Each time you get the microphone you may speak a small permitted say or not. When done speaking or if you have nothing to say you immediately pass the microphone.

Wow, did you ever get that one wrong. See:

Snide answers to Sylvia's History question do not redound well to your status.

I was thinking that a standard would be required that specified the delays, or the means of calculation of the delays, to be used between trying different combinations, so as to avoid the situation where two NICs undermine each other's attempts to find a working combination.

Sylvia.