USB provides a high-speed way to connect devices like: ZIP drives, digital cameras, scanners, printers, and more. USB simultaneously supports up to 127 devices with each being hot swappable. USB can transfer data at up 12Mbps over cable lengths no longer than 5 meters (16.5 ft.). Because of its popularity, most computers come with several USB ports, however, with older systems you need to install a controller card. Additionally, hubs can be added that allow both more connection points as well as extending the usable length.