Distribute power along its own cable so low-consumption devices can operate without a separate power cord. USB replaces a variety of serial and parallel port connectors with one standardized plug and port combination. Courtesy of Kavi . For example, you can plug a keyboard into the computer and then plug a mouse into the keyboard. USB works at 12 Mbps and the even newer USB2 will offer much higher transfer speeds.
Most computers come with one or two USB ports.
However, you can connect hubs to those ports to add connections, much like you might plug a multi-socket extension cord into a wall socket so you can plug in all of your computer equipment. Sometimes referred to as IEEE 1394, Firewire is much faster than USB and is designed to connect up to 63 consumer electronics devices such as digital camcorders, digital cameras, and digital video disc players and also typical PC devices such as CD-ROM drives, printers, scanners, and hard drives. It also enables high-speed Internet connections. Almost all new computer systems come with a USB port built-in. The faster and more expensive FireWire ports are less common.