Here are some
questions appertaining to USB 2.0, this will gradually added
to as more information becomes available
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| What is USB? |
Universal Serial Bus (USB) is a
connectivity specification developed by the USB Promoter
Group. USB is aimed at peripherals connecting outside the
computer in order to eliminate the hassle of opening the
computer case for installing cards needed for certain
devices. USB provides for ease of use, expandability, and
speed for the end user. Whole ranges of USB peripheral
devices are available including joysticks, scanners, digital
speakers, digital cameras, printers, and PC telephones to
name a few. PC peripheral vendors now have an ease way for
consumers to add new capabilities instantly without having
to open the PC, set dip switches, worry about IRQ settings,
or install add-in cards. USB Hot Swapping permits the PC
owner to add new devices without having to shut down and
restart the PC. The USB-compliant PC recognizes the new USB
device and configures the software.
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How fast is Hi-Speed USB 2.0?
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Hi-Speed USB 2.0 operates at 480 Mbps |
Can I connect and
disconnect USB devices with my computer running?
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Yes, USB was designed with a special
feature, called "dynamic connect/disconnect", so you can
plug and unplug devices without having to power-down your
computer. |
When was the final USB 2.0 specification released?
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The spec was released at Microsoft's Windows Hardware
Engineering Conference* (WinHEC) in April 2000. |
Is there a difference between Hi-Speed USB and USB 2.0?
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There is a difference in Hi-Speed USB and USB 2.0. The
difference is that the USB 2.0 specification covers all
three speeds 480 Mbps, 12 Mbps, and 1.5 Mbps. "Hi-Speed USB"
refers to just the 480 Mbps portion of the USB 2.0
specification. We now use the term "USB" to refer to the
12Mbps and 1.5Mbps speeds. |
I want to extend
my connection to operate a USB device remotely. How can I do
this?
|
USB was designed as a desktop connection.
The maximum length of any connection is 5 meters (16 feet).
You can get around this limitation by using an active
extension cable. This cable contains circuitry to amplify
the signal to prevent loss. You can connect up to 5 of these
cables in series. |
What is USB On-the-Go?
|
USB On-the-Go addresses the growing need for mobile
interconnectivity by allowing a USB peripheral to
communicate directly with another USB peripheral. |
| Are their any
limits to the power that can be drawn from a USB connection? |
Most USB devices get their power directly through the USB
connection, so there is no need for external power supplies.
The USB connection on your computer will furnish 5 volts DC
at up to 500 milliamps. Drawing more than 500 milliamps will
shut the port down. Some USB connections limit the current
to less than 500 milliamps. This is common in laptop
computers. The original Apple iMac limited the current to
200 milliamps. If you use a non-powered hub, the current
from each port will be limited to approximately 500
milliamps, divided by the number of ports on the hub. It is
good practice to use a self-powered hub, which has its own
power supply, to make sure each port has a full 500 milliamp
capability
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| How many USB
peripherals can I connect at once? |
Technically, you can connect up to 127 individual USB
peripherals at one time. Due to the fact that some devices
reserve USB bandwidth, the practical maximum of devices is
less than the theoretical maximum. However, PCI-USB add-in
cards provide an independent USB bus to which even more
peripherals can be connected.
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What is the "Hi-Speed logo" and what does it represent?
|
The "Hi-Speed logo" is a trademark-protected logo for
use by qualified licensees. The logo is a guarantee to the
consumer that the product has undergone compliance testing
for quality |
What is the
difference between USB 1.1 and USB 2.0?
|
USB 2.0 is the newest version of the USB
specification. There are two important facts about USB 2.0.
First, USB 2.0 is 40 times faster than USB 1.0. This is
important for devices that require higher speed, such as USB
Hard Drives, CDROMs, CDR/W and Flash Card Readers. It is not
important for low speed devices, such as keyboard, mouse, or
even a USB to Serial Converter. Second, it is backward
compatible with USB 1.1, so USB 1.1 devices can plug into a
USB 2.0 connection. USB 2.0 devices can also plug in to a
USB 1.1 connection, but they will operate at slower speeds.
Many new computers now come with USB 2.0 connections. You
can connect USB 1.1 or USB 2.0 devices to these ports.
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| What does it mean
when a product is USB compliant and why should I care? |
Compliance means products that are called
USB products are really built to match the description in
the USB specification. This is important to consumers
because if all products are in compliance with the
specification they would by definition work together
perfectly. 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. Conscientious
manufacturers do a great deal of testing on their own and
use compliance test programs like the one sponsored by the
USB-IF organization.
Click
here to learn more about compliance testing.
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Where can I get more info on Hi-Speed USB 2.0 in
general?
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If you have not found what you are after here, the
USB-IF web site is the definitive source for all
information pertaining to USB 2.0. |
| What are the best
applications for USB? |
USB plays a key role in three fast-growing
areas: digital imaging, PC telephony and multimedia games.
The presence of USB means that PCs and peripherals will work
together, with a high degree of reliability, in these
exciting new application areas. USB opens the door to new
levels of innovation and ease of use for input devices, such
as the new generation of "force-feedback" digital joysticks.
There are also brand new opportunities for all types of
peripherals from printers to scanners to high-speed
communications such as Ethernet, DSL, ISDN or satellite
communications.
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Is there a plan for USB 3.0
or a faster USB |
No, wired USB has come to an end with the
introduction of the Certified Wireless USB 1.0 approved in
May 2005. Everything will start to go wireless when wireless
USB hub & USB dongles begin appearing in Q2 2006. It will
most likely take about a decade or even longer for
everything to move from USB 2.0 to WUSB.
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| What is USB 2.0? |
|
Also
referred to as Hi-Speed USB, USB 2.0 is an
external bus that supports data rates up to 480Mbps.
USB 2.0 is an extension of USB 1.1. USB 2.0 is fully
compatible with USB 1.1 and uses the same cables and
connectors. Hewlett-Packard, Intel, Lucent,
Microsoft, NEC and Philips jointly led the
initiative to develop a higher data transfer rate
than the 1.1 specification to meet the bandwidth
demands of developing technologies. The USB 2.0
specification was released in April 2000 |
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| When was USB
introduced and how has it moved on? |
USB 1.0 - Made officially
available in January 1996, USB 1.0
supports speeds of 1.5Mbps
(low-speed) and 12Mbps (full-speed).
USB 1.1 - Appearing in
September 1998, USB 1.1 is sometimes
considered a clarification of the
USB 1.0 specification, and also
supports speeds of 1.5Mbps and
12Mbps. Host system specifications
between USB 1.0 and 1.1 are
identical, but USB 1.1 added
information regarding USB hubs.
USB 2.0 - Introduced in April
2000, USB 2.0 vastly increases the
speed of USB from 1.5Mbps and 12Mbps
by forty times all the way up to a
whopping 480Mbps (high-speed),
although USB 2.0 is still backward
compatible with USB 1.0 and 1.1.
USB On-the-Go - The newest
USB standard, USB On-the-Go was
developed as a way to enable USB
peripherals to use a device other
than a PC as a host. Using this USB
communications method, you can
directly connect two devices such as
cell phones and PDAs directly to one
another.
Wireless USB - Made available
in May 2005 to companies to produce
gear based on the technology, USB
has gone wireless. Specified to
deliver a fast rate of 480Mbps at 3
meters and 110Mbps at 10 meters,
wireless USB will likely take off in
waves if it meets its promises and
goals. Wireless USB is expected to
start appearing in products as soon
as the beginning 2006.
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