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Electronics
U
USB:
Universal Serial Bus
Universal Serial Bus (USB) is a protocol for computer peripherals to
communicate with their host computers. Peripherals include digital audio,
telephone interfaces, cable boxes, printers, monitors, keyboard, mice and
scanners. USB supports both low (1.5 Mbs) and medium (12.5 Mbs) speeds,
such that keyboards and mice can use the low speed, while digital cameras
and printers needing faster throughput can use the higher speed.
USB may be implemented for communications activities, thereby allowing for easy interconnecting of computers and telephony, including digital telephones, modems and answering machines. USB enables new devices that were previously unused in computers, such as digital cameras. As the connection of communication systems and computers becomes more prevalent, USB will allow for a consistent, well-defined peripheral development.
One significant benefit of USB is the USB standard, so that true "plug and play" can be a reality. If a consumer buys a USB joystick or mouse, they can plug it into their USB systems and immediately begin using it. This is possible because USB peripherals are self-identifying. There is much less cabling because all the peripherals can communicate on the same bus, instead of each of them requiring its own cabling. This also allows for an expansion in the number of peripherals possible, because more ports are made available.
Another advantage is the ease of integration and design. Someone that builds a lot of peripherals doesn't have to learn a new protocol for each one. Although digital cameras and keyboards require different speeds, they can use the same USB standard.
USB permits real-time data for audio and compressed video, as well as the versatility to handle both periodic and irregular data transfers. Storage FIFOs can be increased as needed for the application. USB will increase the capabilities of the PC and greatly simplify the introduction of new peripherals.
Up to 127 devices with bandwidths up to 12.5 Mbs, can be sustained by USB. The same bundle of wires can manage multiple isochroous and asynchronous transfers between the host and the peripheral devices.