Ethernet... how does it work?

I used Ethernet the first time at home with my brother.

We use to have 2 486 machines and with a 15 meters coaxial cable we were
actually able to play incredible matches at DOOM :)

I never stopped to reflect on how Ethernet works: yes there are packets,
yes they are sent around, ... but this is "software level".

How does it work, down to the electric signals level?

Here I found 2 nice links that explain more about Ethernet...

• wikipedia
  
• a primer