Firewire

The IEEE 1394 standard is a fast, scalable, low-cost digital interface. It was conceived by Apple® Computer and developed within the IEEE 1394 Working Group. It is generally referred to as FireWire™ the Apple trademarked name—although other companies may use different names, such as I-link and Lynx, to describe IEEE 1394. FireWire promises to integrate personal computers with the world of consumer electronics.

Because FireWire is an all-digital interface, there's no need to convert digital data into analog for data transmission. This leads to perhaps one of the most important uses of FireWire: as a digital interface for consumer electronics and AV peripherals. Because FireWire is a peer-to-peer interface, it makes it possible to dub from one device (a digital video camera, for instance) to another without a computer. It also enables multiple computers to share a given peripheral without any special support in the peripheral or the computers.

FireWire supports data rates of 100, 200, and 400 Mbps, and it supports up to 63 devices with a maximum cable length of 4.5 meters between devices. The maximum number of hops in a chain is 16 for a total maximum end-to-end distance of 72 meters. The IEEE 1394 standard supports daisychaining and branching or peer-to-peer implementations. Connections can be free-form, mixing branches and daisychains.

In addition to its high speed, FireWire supports isochronous, as well as asynchronous, data delivery, providing a guaranteed data rate without lags or slowdowns. Because the standard supports guaranteed delivery of time-critical data, it enables applications to use smaller buffers, lowering costs.

This makes it ideal for applications such as digital audio and video, which demand real-time data transfer. A FireWire interface combined with one of the new high-quality, low-cost DVD recorders enables a Macintosh user to capture broadcast-quality video.

FireWire cable is lightweight, flexible, and inexpensive—a vast improvement over bulky and expensive SCSI cables. And, unlike many older interfaces, you never need device IDs, jumpers, DIP switches, screws, latches, or terminators.

There are two types of FireWire connectors: 6-pin and 4-pin. The 6-pin connector, usually found on computers, provides two pairs of wires for signals and one pair of wires to provide power to external equipment. Many FireWire computer peripherals draw their power directly from the interface.

Computer peripherals using 6-pin FireWire connectors generally feature at least two, and often three, FireWire connectors for daisychaining.

The 4-wire FireWire connector is usually found on consumer electronics such as camcorders, VCRs, and video game systems. It provides four signal wires but no power wires. Devices using the 4-pin FireWire connection generally have only one connector and aren't daisychained. When using a device such as a camcorder with your PC, you'll need a 6-pin-to-4-pin cable to convert the interface.