A form of data bus -- a system of wiring that transmits information between the components of a computer. A data bus can be either internal or external; the latter connects to peripherals such as the mouse, printer, keyboard, etc. USB is an external data bus designed by a consortium of computer makers including Compaq, Digital, and IBM. It can connect to as many as 127 peripherals and enable you use them all at once. It supports data transfer rates up to 12MB/sec, making it suitable for even high-bandwidth applications such as video.