1. This is the popular term and acronym for Universal Serial Bus. The name is somewhat incorrect in that the bus is not only serial but has other I/O properties as well. It is in fact a totally new external bus standard that in versions 1.0 and 1.1 supports data transfer rates of 12 Mbps (12 million bits per second) in the specification, though in reality usually averaged about 1.5 Mbps, and spans different platforms as well. A single USB port can be used to connect up to 127 peripheral devices, such as mice, modems, speakers, cameras, scanners, printers and keyboards. USB also supports Plug-and-Play (PNP) installation, hot plugging and multiple data streams. USB competes with DEC's ACCESS bus for lower-speed applications USB supports hot plugging. Starting in 1996, a few computer manufacturers including Compaq, Digital Equipment Corp, IBM, PC Co., Intel, Microsoft, NEC and Northern Telecom, started including USB support in their new machines; the orgainzation behind the support is WWW.USB.ORG. The early versions (1.0 and 1.1, 1998) are now termed Legacy USB in most current BIOS listings. USB 2.0 is the current specification. The USB 2.0 specification touts a 40 times faster data rate, among other improvements. Apple claims that it wasn't until the release of the then hot selling iMac in 1998 that USB became widespread. Clone PC makers say THAT is apple sauce, rotten to the core! No matter who started it, USB is expected to completely replace serial and parallel ports because of the high transfer rates and ease of implementation. Few admit that it was originally designed to replace SCSI operations, however, ALL of the SCSI 1 and 2 standards are part of the specifications.