Eli5: how did swapping the orange and blue cables become the “normal” configuration for Ethernet while having them all in order (crossover) is only for specific uses?

Question

Eli5: how did swapping the orange and blue cables become the “normal” configuration for Ethernet while having them all in order (crossover) is only for specific uses?

In: 3

Answer 1

Up to 100 Mbps, even if the ethernet cable might have 8 wires in it, only 4 of them are actually being used. Two to transmit and two to receive. The crossover cable swap connects send to receive and receive to send on the other end.

With 1000 Mbps and above all 8 wires are in use, and the standard says that the machine has to autodetect the wiring so you can skip the whole thing and just wire both ends the same way.

These days pretty much everything works at gigabit speeds, so you can pretty much forget about the whole crossover cable thing unless you work with some very old hardware.

Answer 2

AT&T did it their way, and they put in more infrastructure, it was easier to match then to have it not work and do it over