Cat5 and cat6 cables are used for computer network cabling, most commonly for Ethernet cabling. The "e," as in "cat5e," stands for "enhanced." Cat6 cable reduces interference between the conductors and is rated for higher transmission speeds and bandwidth than cat5 cable. There are specifications for cat 5, cat5e and cat6, but the next level would be cat6a, even though cat6e is being sold as an enhanced cat6 cable with higher speeds than plain cat6.
Cat5 cable has been widely used since 100 megabits per second (Mbps) networks became common in the 1990s. With higher network speeds going up to 1000 Mbps, or gigabit Ethernet, cat5e was introduced to address this speed requirement. Gigabit Ethernet represents the limit of the cat5 specification, so cat6 was introduced to handle still higher speeds. It is certified up to 10 gigabits per second (Gbps). There is no specification for cat6e, but suppliers are offering such cables as non-standard enhanced cat6 cables.
Separation of Pairs
The key limiting factor for cat5 cable speed is the interference between the four pairs of conductors. Cat 6 cable has a longitudinal separation that runs the length of the cable and isolates the four pairs in separate chambers. To further enhance transmission performance, cat6 cables may have larger #23 conductors instead the #24 conductors present in cat5 cables. The result is that the cat6 cable has far lower levels of internal interference and can handle higher speeds, since the signal-to-noise ratio is higher.
Connectors for cat5 and cat5e cables are identical, but those for cat6 have subtle differences. All are the RJ45-type of connector and will fit into RJ45-type sockets. Pin assignments are also identical for all three cable types and for cable sold as cat6e. Connectors for cat6 cables have slightly larger holes where the individual wires enter the connector to accommodate the slightly larger conductor size. More importantly, the conducting connector material and the details of the conductor arrangement are designed to enhance transmission to match the characteristics of the cable.