I understand that a network card detects collisions because their signal has a higher amplitude than normal signals. But why is that signal of higher amplitude?
For example, say we have the simplest of cases, two computers communicating half-duplex on one wire and they both transmit at the same time, a collision occurring:
A |------>-<------| B
Why does the current intensity arrive at the stations at a higher level? The currents are opposed one to each other.
Most probably I'm missing basic physics here, but I could sure use an explanation...