Straight-Through vs Crossover Cables

Two Ethernet cables can look identical on the outside yet behave very differently inside. The difference is whether the two ends use the same wiring standard or different ones. This gives us straight-through and crossover cables. Knowing which to use between two devices is a classic Network+ topic, even though modern hardware has made the choice less critical than it once was.

A straight-through cable uses the same standard on both ends — either T568B on both or T568A on both. Pin 1 connects to pin 1, pin 2 to pin 2, and so on. This is the everyday cable that connects a computer to a switch or a switch to a router. The vast majority of patch cables you buy are straight-through.