Universal Serial Bus

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universal serial bus

[‚yü·nə‚vər·səl ‚sir·ē·əl ′bəs]
(computer science)
A serial interface that can transfer data at up to 480 million bits per second and connect up to 127 daisy-chained peripheral devices. Abbreviated USB.

Universal Serial Bus

(hardware, standard)
(USB) An external peripheral interface standard for communication between a computer and external peripherals over an inexpensive cable using biserial transmission.

USB is intended to replace existing serial ports, parallel ports, keyboard, and monitor connectors and be used with keyboards, mice, monitors, printers, and possibly some low-speed scanners and removable hard drives. For faster devices existing IDE, SCSI, or emerging FC-AL or FireWire interfaces can be used.

USB works at 12 Mbps with specific consideration for low cost peripherals. It supports up to 127 devices and both isochronous and asynchronous data transfers. Cables can be up to five metres long and it includes built-in 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.

Before March 1996 Intel started to integrate the necessary logic into PC chip sets and encourage other manufacturers to do likewise. It was widely available by 1997. Later versions of Windows 95 included support for it. It was standard on Macintosh computers in 1999.

The USB 2.0 specification was released in 2000 to allow USB to compete with Firewire etc. USB 2.0 is backward compatible with USB 1.1 but works at 480 Mbps.

References in periodicals archive ?
Option for transmitting USB 1.1, bi-directional IR or RS-232 signals
This is in contrast with older USB 1.1 adapters, which only offer 12Mbps transmission speeds over USB.
The RK-DVX2U-A features transparent USB 1.1 signal extension, with full support for all USB 1.1 devices and an integrated 4-port hub in the receiver.
The USB interface is compatible with both USB 1.1 and USB 2.0 standards.
Each path is capable of supporting USB 1.1 or USB 2.0 with negligible impact on the cabling distance supported by USB devices.
The drive has a speed of 5,400 RPM, and the data transfers top out at 480 Mb/s with a USB 2.0 high-speed connection (12 Mb/s maximum with a USB 1.1 connection).
It is also Windows, Macintosh and Linux compatibility with USB 1.1 and USB 2.0 interface, packed with limited-lifetime warranty from the manufacturer and are available immediately at www.TopTechProducts.com and www.amazon.com at $24.99.
* 1 USB 2.0 "B" port - backwards compatible with USB 1.1
Its USB 1.1 computer connection downloads images in less than 3 seconds, and its autoguiding port with a modular jack makes for easy connection to most telescope mounts that conform to SBIG's ST-4 standard.
2: You make reference to "USB 1.1, 1.2, 1.3" as allowing passage of DVD-A, DSD, and newer high-def A/V formats respectively, but there is no USB 1.2 or 1.3, as far as I know--it skipped directly from 1.1 to 2.0.
The newer USB 2.0 drives can be used with computers that have older USB 1.1 interfaces, only they'll run slower.