10/100BASE-T Crossover Cable

When connecting two computers together using Ethernet Network Interface Cards (NICs), there are two options:

The first is to use a Crossover Cable - which is a specially modified ethernet cable consisting of CAT5 twisted pair wiring that has eight-pin connectors on each end wired in the mismatched order shown below.

    RJ-45        RJ-45
  Connector    Connector
  ----------------------
    pin 1   ->   pin 3
    pin 2   ->   pin 6
    pin 3   ->   pin 1
    pin 4   ->   pin 4
    pin 5   ->   pin 5
    pin 6   ->   pin 2
    pin 7   ->   pin 7
    pin 8   ->   pin 8

You can purchase a crossover cable online from Cables-N-More here or you can just make one yourself if you have the time, energy and parts.

The second option is to use a Hub. If you employ a hub, it takes care of the crossover function internally negating the need for a crossover cable. In that case you use standard Ethernet.