Universal Serial Bus (USB) is an industry standard that defines the cables, connectors and communications protocols used in a bus for connection, communication, and power supply between computers and electronic devices. The USB specification is maintained by the USB Implementers Forum (USB-IF), an industry body.
USB was designed to standardize the connection of computer peripherals (including keyboards, pointing devices, digital cameras, printers, portable media players, disk drives and network adapters) to personal computers, both to communicate and to supply electric power. It has become commonplace on other devices, such as smartphones, PDAs and video game consoles. USB has effectively replaced a variety of earlier interfaces, such as serial and parallel ports, as well as separate power chargers for portable devices.
USB can connect up to 127 peripheral devices, such as mice, keyboards, digital cameras, printers, personal media players, and external hard drives. USB also supports Plug-and-Play installation and hot plugging. A device plugged into a USB port can be identified without restarting the computer. USB drivers can be installed automatically or manually.
USB is a serial bus as it uses a single data line for communication. There are two wires for power in USB cable which can deliver up to 5V and 500 milliamps of current. USB cables have an A plug on one end and a B plug on the other end. USB 2.0 cables can have speeds up to 480Mbits/sec and USB 3.0 cables can reach speeds up to 5 Gbits/sec.
USB ports can be found on most PCs and laptops, as well as on some other devices such as game consoles, smart TVs, DVD players and digital cameras. USB is used to add devices that are not built into the computer, such as scanners, external hard drives, and webcam accessories. USB cables are also commonly used to transfer files between computers or to charge portable devices.
