Universal Serial Bus. A computer interface standard introduced in 1996 to replace the previous standard serial and parallel ports more commonly used.
The USB1.1 interface operated at up to 12Mb/s, but this was superseded in 2000 by USB2.0 which operates at up to 480Mb/s. Most USB interfaces can also provide a 5V power supply to connected devices.
USB3.0 was launched in 2008 and is claimed to operate at rates up to 5Gb/s. USB connectors can be indentified by having a blue insert in the Type-A sockets and the letters SS (SuperSpeed).
The latest edition, USB3.1 (launched in 2013) offers transfer rates of 10Gb/s, approaching that of the first generation of Thunderbolt interfaces. Like earlier USB interfaces, the USB3 format provides a 5V power supply, but the current rating has been increased from USB2.0's 200mA (1.0 Watts) to 900mA (4.5 Watts), and sockets designated as charging sockets can manage 1500mA (7.5 Watts).