Networking Fundamentals

Crossover cable

A crossover cable is used when connecting two similar devices together. Similar devices would be a PC to a PC, a switch to a switch, a router to a router, and a PC to a router. The last one on the list is a good example of how the similarity of devices is based on transmit and receive pins. While crossover cables exist, it is highly unlikely that you will use one. The simple reason for this is that most modern network cards are capable of identifying whether a pin should be used to transmit or receive. As shown in the following diagram, with a crossover cable, pin 1 is connected to pin 3, while pin 2 is connected to pin 6:

Figure 8.14: Crossover cable

The next combination is the rollover cable.