Universal Serial Bus
A serial bus standard developed in the mid-1990s. USB connections attach personal computers to keyboards, printers and other peripherals, delivering power to devices on the bus and eliminating separate power cords. The USB standard provides a data rate of 12 megabits per second and supports up to 127 devices. It's slower than its rival FireWire (IEEE 1394), but is less expensive to implement. USB delivers complete plug-and-play capabilities to devices as well as hot-swap capability. And because of the small size of the USB connector, it can be used on notebook and handheld computers.