Defining what is Cat 5 wiring is a difficult task for your average person. Although many people have heard about Cat 5 wiring, most of them have no idea exactly what it is. Cat 5 stands for Category 5 wiring, which is currently top of the line. It was created to surpass the Cat 3 wiring which could only handle 10 Mbps. The Cat 5 wiring also supports sound frequencies up to 100 MHz. Category 5 cables can handle up to 100 Mbps, almost 10 times that of regular Cat 3 cables. The cabling has 4 twist.