User`s manual

4
Introduction to USB
USB stands for Universal Serial Bus. It is a standard for connecting
external devices to your computer quickly and easily. One of the nice
things about USB is that power can be provided to the USB device through
the USB cable. Some devices such as printer need more power than the
USB ports can provide, so those devices will have to use an external power
source. USB also allows the device to be connected and removed from the
PC without the need to shut down the computer.
Currently many USB products are widely available on the market and
more are being developed for future release. Because of the high speed of
the USB interface, a USB hub can be used to connect more than one USB
device to one USB port at one time. The USB standard specifies that up to
127 devices can be connected to your computer.
USB is fast enough for webcams and other video devices to transfer
large amounts of data. The USB specification allows for two different
speeds. A lower speed of 1.5Mbps is used in low power and low speed
devices. The faster speed of 12Mbps is used for most devices, especially
audio and video USB devices.
The most used standard for USB is version 1.1. A new version called
USB version 2.0 will be much faster at 400Mbps and will replace version
1.1 as the standard for the market.