USB Universal Serial Bus Finalized in 2001, Universal Serial Bus (USB) 2.0 supports Plug-And-Play and can be used on Hot-Plugging without turning the power off. Each USB port could connect 127 devices at the same time. The transmission speed is up to 480MBPS, which is 480 times of USB 1.1 and meanwhile is totally compatible to USB 1.1 at the same time. The goal of the new serial bus is to broaden the range of external peripherals that can be used on a computer.