What is the difference between the USB and IE1394 standards?

Both FireWire and USB are technologies used to connect devices to a computer and transfer data quickly. FireWire is also known by the term IEEE1394 High Performance Serial Bus, and USB stands for Universal Serial Bus. The main difference between the two is that FireWire is made to handle more data than USB, particularly audio and visual information. For example, a2.0 USB can handle a data transfer rate of480 Mbps, whereas an800 FireWire can take on800 Mbps. However, a2.0 USB can manage127 devices while an800 FireWire can only manage up to63 devices. Both work using the plug-and-play, hot-pluggable technology, meaning you can plug a device into your computer while the 

USB supplies3 to5 Volts of power to connected devices while IEEE1394 can supply upto  30 volts and higher power making it better suited to power-hungry, high-bandwidth devices.

FireWire is often used on devices that require very fast sustained data transfer rates, such as DV camcorders, audio interfaces, external hard drives, and professional scanners and printers