USB is termed as universal serial bus. It is a device developed in the mid- 1990's that defines the cables, connectors and communications protocols used in a BUS( communication system that transfers data between computers). It is used in a BUS for connection, communication and power supply between computers and electronic devices.
USB was designed to standardize the connection of computer peripherals to personal computers, both to communicate and supply electric power. USB has effectively replaced a variety of earlier interfaces, such as serial and parallel ports, as well as separate power chargers for portable devices.