Ethernet Crossover Cable
Before we see how to make an ethernet crossover cable, let's start with a regular cat5 patch cable. There isn't much difference between a crossover cable and a regular patch cable. Below is what a patch cable looks like.
Here's what an ethernet crossover cable looks like. Notice only one end has changed. Wires 1 and 3 have been transposed, and 2 and 6 have also been transposed.