Universal Serial Bus (USB)
One of the main functions of the USB interface is the possibility of connecting devices to the PC without having to restart the PC (hot plugging). The standard provides power to devices via the bus and a total of 127 devices can be connected via hubs. The complete data transfer via USB is controlled by the PC and is now found on most motherboard chipsets removing the need for a separate interface card. It is possible, however, to expand the USB capacity of a PC by additional host controller boards.