CAT5 cable contains four pairs of copper wire. It supports Fast Ethernet speeds (up to 100 Mbps). As with all other types of twisted pair EIA/TIA cabling, CAT5 cable runs are limited to a maximum recommended run length of 100m (328 feet).
Although CAT5 cable usually contains four pairs of copper wire, Fast Ethernet communications only utilize two pairs. A newer specification for CAT5 cable - CAT5 enhanced ("CAT5e" or "CAT 5e") - supports networking at Gigabit Ethernet[ speeds (up to 1000 Mbps) over short distances by utilizing all four wire pairs, and it is backward-compatible with ordinary CAT5.
Twisted pair cable like CAT5 comes in two main varieties, solid and stranded. Solid CAT5 cable supports longer length runs and works best in fixed wiring configurations like office buildings. Stranded CAT5 cable, on the other hand, is more pliable and better suited for shorter-distance, movable cabling such as on-the-fly patch cabling.
Though newer cable technologies like CAT6 and CAT7 have been developed, CAT5 / CAT5e Ethernet cable remains the popular choice for most wired local area networks (LANs), because Ethernet gear is both affordable and supports high speeds.