Universal Serial Bus
From the Simple English Wikipedia, the free encyclopedia that anyone can change
Universal Serial Bus (USB) is a "serial bus" for connecting devices. It is most used on PCs but can also be used on other devices such as the PlayStation 2, PlayStation 3 and the Xbox 360. USB can be used as a power device for charging things and making use of gadgets (lights, fans). Most people use USB for mice, keyboards, scanners, printers, digital cameras, and flash drives. Approximately, there are over one billion USB devices around the world.
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[change] Brief history
The Universal Serial Bus was created about ten years ago. This new technology became an instant success. Ever since USB was introduced different producers of electronic devices thought about the future of the bus. It can provide connection to the computer and other devices like for example laptops and MP3 players.
The bus was introduced by seven companies which represent the leaders in the industry of information technology (IT): Compaq, IBM, Intel, Microsoft, NEC, Northern Telecom, and Digital Equipment Corporation (DEC).
Several years earlier adopters and developers of USB gathered in a special hotel in California to test their devices. The meeting of USB developers had the name of Plugfest. They selected a special hotel that included two rooms: one used for sleeping and the other one for making tests. The meeting lasted three days and in this time the representatives of about fifty companies connected their USB devices to one general host system.
The logo of the USB device also has its own history. Not so many people know that the USB logo was in development for several months. Today we can see the final variant of the USB logo.
- 1994 - Seven companies united to begin the development of USB.
- 1995 - 340 companies formed the USB Implementation Forum.
- 1996 - More than five hundred USB products were already developing around the world.
- 1997 - USB Implementation Forum became richer with 60 more companies.
- 1998 - USB becomes the most popular technology on the market of electronics.
- 2000 - The introduction of USB 2.0. Today it represents the most widely used USB device.
- 2005 - USB becomes wireless.
[change] Different standards
Currently, there are three different USB standards that are in use: USB 1.0, USB 1.1 and USB 2.0. USB 1.0 has almost died out. USB offers 3 different transfer speeds: 1.5 MBit per second (called low speed), 12 MBit per second (Full Speed) and 480 MBit/second (Hi Speed). Hi speed is only available in USB 2.0. Please also note that these speeds are raw data speeds (in Million bits per second). The actual data rate is usually lower (and maxes out at around 320 MBit per second due to protocol overhead.
In order to be able to use the transfer rate hi speed both the USB controller and the connected device need to support it. USB is backwards compatible. A USB2.0 device can be used with a USB 1.1 controller. It will not be able to transfer at 480 MBit/seconds though.
[change] USB Hubs
Almost all computers nowadays have USB ports, most of them support USB2.0. However, the number of ports is usually limited (2,4, or 6 ports are common configuration). USB allows the use of so-called USB Hubs, to add more ports.
The hubs themselves are also USB 1.1 or USB 2.0 compliant. On an USB 2.0 controller, standards can be mixed. Please note however, that devices connected to a USB 1.1 hub will only offer the data rates of USB 1.1.
[change] See also
[change] Other websites
- USB Historical Highlights Find out more on the history of USB
- How Does the Universal Serial Bus Work?
- A Description of the USB System Architecture.
