A
New Way to Connect: USB Device
By
Joe Chow
|
In
recent years, most computers connect to
external devices in a new way, known as
Universal Serial Bus (USB). USB is an
easy way to connect to numerous types
of devices including printers, digital
cameras, game pads, joysticks, keyboards,
mouse devices, and storage devices etc.
As USB is a very commonly used standard,
let us look at it in more detail and see
how it is supported in the University.
USB
versions
The latest version
of USB is called the USB version 2.0; its speed is up to 480 Mbps. However,
some old computers and old USB devices belong to version 1.0 and 1.1,
and they support only 12 Mbps. However, all these versions are inter-compatible.
Support
of USB in CityU
All
the computers in CityU should support
USB 1.1 or above. For Dell desktop PCs
of more than 2 years (e.g. model like
GX200, GX400 and Precision220), they support
version 1.1 only and most of their USB
ports are at the back of the PCs. For
the latest models (e.g. GX260, GX270 and
Precision360), the USB ports, which support
version 2.0, are installed at the front
of the PCs and are normally covered by
a movable door near the bottom of the
PCs. For public PCs like those in lecture
theatres, classrooms and express terminals,
USB hubs are installed. Please find out
more by visiting them or calling us if
you need help.
Connecting
USB devices to your computer
You
can connect a USB device to your computer
while the computer is turned on.
However, DO NOT plug or unplug a USB device,
especially a storage device, while the
device is in use, or you may damage your
files.
If
necessary, connect the USB device to a
power source, as some devices need extra
power to drive. Standard USB port only
provides 500mA which is not sufficient
for most devices. If your USB device does
not have an attached USB cable, then plug
one into a corresponding USB port on the
device and plug the other end of the cable
into an USB port on your computer. A standard
symbol for USB port looks like this:
If your computer doesn't have a free USB
port, you may need to add a USB hub and
connect other USB devices to the ports
on the hub. In fact, you can cascade as
many as 127 devices in this way. You don't
need to install any software to use a
USB hub. Some USB devices, such as some
USB keyboards like those in Lecture Theatres
and most classrooms, contain a hub so
that you can plug additional USB devices
into them.
Common
problems in using USB
If
a USB device doesn't work:
-
If
a message on the screen indicates that
you don't have the necessary software
to operate the device, you may not be
able to connect to the Internet and
automatically download the software
necessary to use the device. You can
also contact the manufacturer of the
device to find out how to obtain and
install the necessary software.
-
Some
devices do not need power but it cannot
support long USB cable due to various
reasons like power diminishing effect,
so make sure the extension cable is
not too long or else you need to install
a USB hub with power in the middle.
This is the reason why some USB devices
are not functioning with the external
USB ports under the keyboards in the
lecture theatres and classrooms. This
problem has been sorted out recently
by installing new USB hubs in front
of the PCs near the floppy drive.
-
If
the device has a power cord, make sure
the cord is plugged into a working electrical
outlet and the device is turned on.
-
Some
USB devices, such as printers, need
to warm up for a few minutes after you
turn them on. For more information,
see the documentation that comes with
the device.
- Make
sure the USB cable connectors are plugged
in properly and that the cables aren't damaged
or frayed.
- After
unplugging the device from the USB port, wait
for a few seconds before you plug it back
in again.
Key
benefits of using USB
- USB
is a very common standard and almost every
computer running nowadays supports it.
- There
are USB converters that can convert other
standards to USB standard. So it is highly
compatible.
- You
can plug and unplug devices while your computer
is turned on. The installation is very simple.
- You
can attach up to 127 devices to each USB port
on your computer.
- You
can transfer information at a fast rate, up
to 48 Mbps for each USB port (USB version
2.0) on your computer. That is near the speed
of an ordinary IDE hard disk transfer rate.