The designers of the Universal Serial Bus (USB) had several particular goals in mind when they created the USB standard:
- Low implementation cost, so that USB could be used in cheap peripherals like mice and game controllers
- Low cabling cost
- Lots of devices on the bus
- Good speed characteristics for things like printers
The idea was to create a system that would replace all of the different ports on computers (parallel ports, serial ports, special mouse and keyboard ports, etc.) with a single standard. USB achieved all of these goals very effectively, and there will come a day in the not-too-distant future when computers will have nothing but a set of USB connectors on the back.
FireWire, originally created by Apple and later standardized as IEEE-1394, actually preceded USB and had similar goals. The difference is that IEEE-1394 was originally intended for devices working with lots more data -- things like camcorders, DVD players and digital audio equipment. IEEE-1394 and USB share a number of characteristics and differ in some important ways. Here's a summary:
- Like USB, IEEE-1394 is a serial bus that uses twisted-pair wiring to move data around.
- However, while USB is limited to 12 megabits per second, IEEE-1394 currently handles up to 400 megabits per second.
- USB can handle 127 devices per bus, while IEEE-1394 handles 63.
- Both USB and IEEE-1394 support the concept of a isochronous device -- a device that needs a certain amount of bandwidth for streaming data. This mode is perfect for streaming audio and video data.
- Both USB and IEEE-1394 allow you to plug and unplug devices at any time.
Most digital video cameras have an IEEE-1394 plug. When you attach a camcorder to a computer using IEEE-1394, the connection is amazing. With the right software the computer and the camera communicate, and the computer can download all of the scenes on the tape automatically and with perfect digital clarity. As prices fall, home video production will become trivial!
Here are several interesting links:
- How USB Ports Work
- Adaptec: How Does Firewire Work?
- How does USB compare with FireWire/IEEE 1394 standard?
- IEEE 1394 - Webopedia Definition and Links
- What Is: Firewire
- Tutorial: Audio Distribution and Control using the IEEE 1394 Serial Bus
- Apple: Firewire Technology Fact Sheet (.pdf file)
- White paper: Firewire