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Summary :
This guide provides solutions to frequently asked questions in General
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What Is USB?
USB is a specification that allows computer peripherals to be attached to the
outside of the computer. It eliminates the need to install cards into dedicated
computer slots and reconfigure the system. USB is really an ultimate
plug-n-play specification that no switches or jumpers are required to
configure. One of the top benefits from USB is that users can install hardware without
needing to reboot their computers. USB allows up to 127 devices to
run at the same time on the bus, with hubs connecting to devices to the bus.
The USB also provides a much higher transfer rates than the traditional
RS-232 or parallel-port devices. |
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What does it mean when a product is USB compliant?
Compliance means products that are called USB products are really built to
match the description in the USB specification. This is important to a customer
because if all products match the spec perfectly they would by definition work
together perfectly. The world is not perfect and so compliance testing exists
to help manufacturers measure how well their products match the specification.
There are many ways to make sure products work together and many ways to see if
they match the specification, but compliance testing is one of the most useful.
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What devices support USB?
Almost any I/O (Input/Output) device can be used with USB. They include Mice,
Keyboards, Joysticks, Scanners, Monitors, Zip Drives, Telephones, Cameras and
Printers.
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What is USB 2.0 and will it replace the original?
USB 2.0 runs at a whopping 480 Mbps and features complete backward
compatibility with the original USB. USB 2.0 will most likely not
completely replace its predicator because, simply, a keyboard or mouse doesn't
need 480 Mbps bandwidth. While peripherals won't utilize 2.0, it will be
great for web cams, digital cameras, etc.
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How fast is USB?
USB is designed to run at 12 Mbps with a sub-channel running at 1.5 Mbps.
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What is USB 2.0?
USB specification version 2.0 is the next-generation peripheral connection for
personal computers. It is intended as an upgrade for USB 1.1. Not only the new
standard provides additional bandwidth for multimedia and storage applications
but also offers Plug-and-Play capability and full backward compatibility for
legacy USB devices.
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What is USB Hi-Speed?
USB Hi-Speed is another name for USB 2.0. The official USB Promoter Group
didn't want the new USB 2.0 specification to be seen as a completely new
standard, which may confuse consumers. Therefore, USB 2.0 becomes USB Hi-Speed,
and USB 1.1 gets a new title as USB Basic Speed.
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How fast is USB 2.0?
USB 2.0 has a raw data rate at 480Mbps, and it is rated 40 times faster than
its predecessor interface, USB 1.1, which tops at 12Mbps. Originally, USB 2.0
was intended to go only as fast as 240Mbps, but then, USB 2.0 Promoter Group
increased the speed to 480Mbps in October 1999.
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Will USB 2.0 replace USB 1.1?
Not entirely, because many products such as generic keyboards, mice, joysticks
and audio speakers do not require the faster speed of the new USB 2.0
technology. Only bandwidth-hungry devices, such as webcams and high-capacity
storage systems, will need all the speed. However, next-generation systems will
come with USB 2 ports rather than USB 1.1
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How do I distinguish between a USB 2.0 and a USB 1.1 device?
New logos designed by the USB Promoter Group allow consumers to easily identify
the new USB 2.0 products. The new colorful logo for USB 2.0 is labeled USB
Hi-Speed, and the new logo for USB 1.1 is labeled with USB Basic Speed.
However, most people won't miss it as manufacturers often label "USB 2.0 READY"
or "40 times faster than USB 1.1" on the boxes.
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Will USB 2.0 arrive on mobile computers?
Yes, but not in integrated solution on laptops. You will need a USB 2.0 CardBus
card. Orange Micro. is shipping USB 2.0 compliant 4-port CardBus card.
Eventually, notebook vendors will adapt to USB 2.0 technology, and we will see
USB 2.0 ports on laptops. This transition won't happen until 2002 at the
earliest.
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What kind of USB 2.0 devices are available now?
Right now, USB 2.0 has held strong in external storage devices like CD-RW
Drives and Hard Drives. Beside applications in storage category, USB 2.0
compliant webcams have yet to arrive in the digital video market. We will also
see to equip with the new USB 2.0 interface to speed up the image download
process.
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How will consumers benefit from USB 2.0?
With speed 40 times more than that of USB 1.1, USB 2.0 broaden the range of
external peripherals that can be used on a computer. Even with multiple
high-speed peripherals connected to a USB 2.0 bus, the system will less likely
to hit the bandwidth bottleneck. The new specification also inherits the
current USB's Plug and Play and hot-swapping capability as well as providing
backward compatibility for USB 1.1 hardware, allowing existing user base to
upgrade seamlessly.
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Does USB support data rates besides 12 Mb/s and 1.5 Mb/s?
Yes. The new hi-speed data transfer rate is 480 Mb/s. There is, however, wide
variation in edge rates. With typical line loads, full speed devices usually
fall in the 12-25 ns range, and low-speed devices typically range 110-225 ns.
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