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Welcome to USB.

Universal Serial Bus (USB) makes connecting devices to your computer faster, easier and virtually limitless. High-speed USB devices are capable of communicating at speeds up to 12 megabits per second. USB makes Plug-and-Play a reality. Simply plug a USB device to your computer- without shutting down and without having to open your computer. Connect up to 127 printers, modems, keyboards, mice, joysticks, scanners, digital cameras, and other USB devices.

The growth of USB products and related services over the next years will be outstanding. USB will soon replace legacy devices, and with most PCs and notebooks shipping with USB ports as well as major operating systems supporting USB, the technology is maturing and gaining momentum. Universal Serial Bus is now the dominant interface for connecting virtually all computer peripherals - printers, scanners, modems, cameras and virtually any other form of computer-connected device.

Universal Serial Bus

USB, or Universal Serial Bus, is a peripheral bus connectivity standard which was conceived, developed and is supported by a group of leading companies in the computer and telecommunication industries - Compaq, DEC, IBM, Intel, Microsoft, NEC, and Northern Telecom. USB was developed with one goal in mind: to make it easier for users to plug-and-play computer peripherals without having to open the box, install cards into dedicated computer slots and reconfiguring the system. The current standard published and implemented on most USB devices is version 1.1.

USB makes it convenient to simultaneously use and connect up to 127 peripherals to a computer without using several connectors, different interrupts and IO addresses. The computer automatically recognizes the device connected and installs the appropriate drivers. It enables computer users to "hot-plug" computer peripherals to their PCs and start using them without having to reboot.

Features of USB

  • One type of device cable. USB also standardizes connectors and cables. USB cables have two connectors: an A connector and a B connector. The A connector is the end that goes into the computer, and the B connector goes into the device. The total cable length between devices must not exceed 5 meters, or 16 feet.
  • Operating System support. USB driver support is built into the latest versions of the Windows and Apple operating systems. It is not compatible with all operating systems. Some USB devices will work with Windows 95 OSR 2.1, but Windows 98, Windows 2000, MAC OS 8.1 or higher offer much more USB support.
  • Two device speeds. Low speed (1.5 Mbps) is mostly used for input devices such as mice and keyboards, while high speed (up to 12 Mbps) is used mostly for video/audio capture devices and storage devices.
  • Hot pluggable. Devices can be attached to and detached from the computer without turning off the system. No jumper or IRQ settings are necessary.
  • Plug-and-Play. Once the device is connected to the computer, the system automatically recognizes the device connected and installs the appropriate drivers.
  • 127 peripherals. USB makes it possible to simultaneously use and connect up to 127 devices to a single bus. The computer typically has 2 USB ports, so USB hubs are used to connect additional devices to the computer. USB hubs have multiple USB ports for connection of USB devices and for daisy chaining one or more hubs.
  • Point to point connection. USB enables devices to be connected in any order, eliminating the need for external terminators.
  • Bus-powered and self-powered. USB supports both bus-powered and self-powered devices. Good examples of bus-powerd and self-powered devices are USB hubs. USB hubs can draw power either from the host device (bus-powered) or from an external AC power supply (self-powered). Each downstream port on a bus-powered hub typically supplies up to 100 mA. On the other hand, each downstream port on a self-powered hub typically supplies up to 500mA.

Bus Topology

USB devices can be connected to the computer either directly through the USB port on the back of the computer or through a USB hub. The Universal Serial Bus connects USB devices with the USB host. There is only one host on any USB system. The USB interface to the host computer system is referred to as the host controller.

The host PC and USB hub each contain a USB controller. This controller is typically mounted on the PC motherboard, on a PCI add-in card or on the hub itself. The controller's function is to manage the USB devices on the serial bus and to help reduce the load on the computer CPU.

USB Devices

USB devices may be attached or detached from the USB host or hub. They may obtain power from an external source and/or from USB through the hub to which they are attached. When a USB device is attached to or removed from the USB hub, the host uses a process known as bus enumeration to identify and manage the device state changes necessary. A USB device must be configured and the host PC is responsible for configuring a USB device. The host typically requests configuration information from the USB device to determine the device's capabilities. This makes it possible for users to plug-and-play their USB devices to the PC.

Human Interface devices - mice, keyboards, joysticks, trackballs, touchpads, gamepads, microphones, video and still image cameras, PC card readers, and scanners
Output devices - text and graphics printers, photo printers and speakers
Storage devices - floppy drives, hard drives, Zip drives Communication devices - infrared devices, ISDN devices, networking equipment and modems
Hubs - standalone, keyboard hubs and monitor hubs.

USB 2.0

As you know by now, USB currently supports a data transfer rate of 12 megabits per second. This high speed gives USB quite an edge over standard serial and parallel connections. And the good news is, USB is getting even faster. Slated to be released by the end of the year 2000, USB 2.0 promises even higher data transfer rates, up to 480 Mbps. Compaq, Hewlett-Packard, Intel, Lucent, Microsoft, NEC, and Philips will jointly lead this initiative, which will enable new classes of high-performance peripherals.

The higher bandwidth of USB 2.0 will allow high-performance peripherals, such as monitors, video conferencing cameras, next-generation printers, and faster storage devices to be easily connected to the computer via USB. The higher data rate of USB 2.0 will also open up the possibilities of new and exciting peripherals. With the increased availability of USB-enabled PCs and USB peripherals on the market today, the need for legacy dependent input/output (I/O) connectivity is decreasing significantly. USB 2.0 will be a significant step towards providing additional I/O bandwidth and broadening the range of peripherals that may be attached to the PC.

USB 2.0 is expected to be both forward and backward compatible with USB 1.1. Existing USB peripherals will operate with no change in a USB 2.0 system. Devices, such as mice, keyboards and game pads, will not require the additional performance that USB 2.0 offers and will operate as USB 1.1 devices. All USB devices are expected to co-exist in a USB 2.0 system. The higher speed of USB 2.0 will greatly broaden the range of peripherals that may be attached to the PC. This increased performance will also allow a greater number of USB devices to share the available bus bandwidth, up to the architectural limits of USB.

Leading the Development of USB 2.0

The companies that are leading the development of USB 2.0 have the expertise needed to focus on a specification that supports higher functionality peripherals. The USB 2.0 core team includes all four members of the USB 1.1 core team (Compaq, Intel, Microsoft, and NEC), and three new members (Hewlett Packard, Lucent and Philips). As with USB 1.1, members of the core promoters group do not intend to charge royalties for essential patents required to implement the USB 2.0 specification.

I/O connectivity is being further advanced with the IEEE 1394 standard. USB 2.0 and 1394 primarily differ in terms of application focus. USB 2.0 will support the full range of popular PC peripherals while 1394 targets connection to audio visual consumer electronic devices such as digital camcorders, digital VCRs and digital televisions.

IEEE 1394 - Similar but not the same

IEEE-1394 technology, also known as FireWireŽ or iLink™ is a high-performance and low-cost digital interface that merges computing electronics into consumer multimedia. It is perfect for high-end users requiring data intensive applications for storage drives, high-quality digital video and audio. With FireWire, you can connect up to 63 devices in one chain and support speeds of up to 400 Mbps, 10 times faster and 9 times as many devices per chain than SCSI. It's plug-and-play and hot-swappable: you can connect and disconnect devices without shutting down your computer allowing flexibility and expandability.


MORE ABOUT USB:

The growth of USB products and related services over the next years will be outstanding. USB will soon replace legacy devices and with most PCs and notebooks shipping with USB ports as well as major operating systems supporting USB, the technology is maturing and gaining momentum. Universal Serial Bus is now the dominant interface for connecting virtually all computer peripherals - printers, scanners, modems, cameras and virtually any other form of computer-connected device. USB related product sales are soaring and are projected to explode in the next milleneum. Now is the time to take advantage of USB's growing market as it creates new solutions for you or your customers.

Belkin Components is your partner in taking advantage of this great opportunity and in providing comprehensive USB solutions for you or your customers and their day to day activities - work, play, print, internet connection, share files, capture images, mobile computing, and so on. Belkin designed all its USB products with ease of use, expandability and compatibility in mind. Through our leadership positioning in driving USB technology to the channel, our innovative line of USB connectivity products, and our building of the industry's leading USB development team, Belkin Components has positioned itself to be the premier supplier of USB products, today and tomorrow.


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