IEEE 1394

IEEE 1394 (also known by Sony's "iLink", Apple Computer's "FireWire" brand names and DV port) is a 1995 personal computer and digital video serial bus interface standard offering high-speed communications and isochronous real-time data services, developed primarily by Apple Computer. It is defined in IEEE 1394.

The system is commonly used for connection of data storage devices[?] and digital video cameras. It is used instead of the more common USB due to its faster speed, and because it does not need a computer host. It is also does not need to send a signal telling the other component that it is "alive": a data interruption that makes USB ineffective for professional video work. However the small royalty that Apple has demanded from users of FireWire and the more expensive hardware needed to implement it has prevented FireWire from displacing USB in low-end mass-market computer peripherals where cost of product is a major constraint.

It can daisy-chain together up to 63 peripherals in a tree-like structure (as opposed to SCSI's linear structure). It allows peer-to-peer device communication, such as communication between a scanner and a printer, to take place without using system memory or the CPU. It is designed to support plug-and-play and hot swapping[?]. Its six-wire cable is not only more convenient than SCSI cables but can supply up to 60 watts of power, allowing low-consumption devices to operate without a separate power cord.

FireWire 400, tracking the IEEE 1394a specification, can transfer data between devices at 100, 200, or 400 Mbps with four or six-pin cables. Cable length is limited to 4.5 metres but up to 16 cables can be daisy-chained[?] yielding a total length of 72 metres under the specification.

FireWire 800, which tracks the IEEE1394b standard and was introduced commercially by Apple in 2003, allows an increase to 800 Mbps with a nine-pin cable. It does not have the cable-length limitation of FireWire 400. Further speed increases to 2 Gbps are planned.

Some expensive camcorders[?] have included this bus since 1995. All Macintosh computers currently produced have built-in FireWire ports. With this new technology, FireWire, which was arguably already slightly faster, is now substantially faster than USB 2.0.

See also

• HAVI, FireWire to control Audio and Video hardware.
• Universal Serial Bus(USB)

Additional Resources

• 1394LA (http://www.1394la.com/) administers the rights for patented inventions necessary to implement IEEE 1394.