USB 1.1 works at 12 Mbps with specific consideration for low-cost peripherals, supports up to 127 devices over cables up to five meters long, and includes power distribution for low-power devices. It supports daisy chaining through a tiered star multidrop topology. A USB cable has a rectangular ‘Type A’ plug at the computer end and a square ‘Type B’ plug at the peripheral end. A mini version of the plug is used for very small devices such as digital cameras.
USB provides a 5-volt supply at up to 500 mA for powering low-power devices. It is now available on virtually all personal computers and many printers, scanners, etc. It is supported by all the popular operating systems providing plug-and-play.
The USB 2.0 specification, released in 2000, allows USB to compete with Firewire, etc. USB 2.0 is backward-compatible with USB 1.1 but works at 480 Mbps. Most, if not all, modern systems support hot-swapping of USB devices.
USB • abbr. Comput. universal serial bus, a connection technology for attaching peripheral devices to a computer, providing fast data exchange.
USB flash drive
USB flash drive • n. Comput. an external flash drive, small enough to carry on a key ring, that can be used with any computer with a USB port.