Universal Serial Bus [USB]


(n.) An input/output (I/O) bus capable of data transfer at 12 megabytes per second (MBps) with up to 127 devices connected in a daisy chain. The USB specification was published in 1996 by a consortium of companies led by Intel Corporation, including Compaq, Digital Equipment Corporation, IBM, Microsoft, NEC Technologies, and Northern Telecom. In addition to a keyboard, a mouse, and a printer, a peripheral such as a CD-ROM drive or a modem may be connected to a single port on a PC. Typically, each device connected to a computer uses its own port. USB supports multiple isochronous data streams for multimedia applications. The USB specification supports self-identifying peripherals, a feature fully compatible with plug and play (PnP) systems. USB devices may be hot plugged, which means that power does not have to be turned off to connect or disconnect a peripheral. The operating system must support USB in order for it to function. Original versions of Windows 95 and Windows NT 4.0 do not support USB, but the OEM Service Release 2 (OSR-2) release of Windows 95 does. Windows 98 and Windows NT 5.0 fully support USB. It is expected that USB will become a primary means of connection in IBM-compatible PCs. Most major hardware, software, and telecommunications providers support USB.