Universal Serial Bus
Universal Serial Bus, or USB for short provides a single, standardized, easy to use way to connect devices to a computer. It uses a much higher data transfer rate than many common serial data formats. You can attach up to 127 individual devices to your computer using USB. USB can also supply enough power to smaller USB devices taking away the need to plug them into an external power source. This comes in handy for remote notebook useage.
Some common examples of USB devices include:
External hard drives
If the device you are installing is new to the computer, Windows will auto detect it and asks for the driver disk if needed. If the device has already been installed, the computer will start using the device right away. USB devices can be connected and disconnected at any time making them hot swappable. Typical USB connectors have an A connector on one side and a B connector on the other. You can have other types of connectors for different devices such as cameras and cell phones.