The first thing I had to learn the hard way is that network cable wiring has nothing
to do with logic.. Also remember, that it is very rare to have to make a cross-over cable.
Most Hubs and Switches these days have a uplink port. Using a straight through cable
plug into the uplink of one Hub/Switch and plug the other end into a regular port of the
other Hub/Switch. I do believe you need a crossed cable if you intend to connect two
computers card to card. i.e. without a hub or switch. Good Luck!!
Proper Wiring of an RJ-45 Cable for 100 Mbit Ehternet.
This shows the proper wiring of an RJ-45 Connector.
This is a little better picture of what's going on.