About FireWire®

Firewire is a communication technology that was developed by Apple® in the early 1990s, at about the same time as USB. The original Firewire standard is known as IEEE-1394a, DV or as i.Link® (Sony®'s implementation of the standard). Occasionally it is referenced as Firewire 400 due to its maximum data transfer speed of 400 Mbps. Because it was more costly to implement than USB, Firewire didn't become as popular an interface for peripheral devices. However, its fast performance and stability have made it a popular choice for high-bandwidth applications such as digital video and portable storage.

One of Firewire's biggest advantages over USB is that it does not require a host controller. This means that two Firewire devices can communicate without the use of a computer. For example, video can be dubbed from one DV camcorder to another through the use of a Firewire connection. More recently, the development of FireWire 800 (IEEE-1394b) arose with the maximum data transfer speed of 800 Mbps. Remember that for adapter cables with one 4- or 6-pin connector and a 9-pin connector, the maximum transfer rate remains 400 Mbps.

For non-powered devices, the 4-pin FireWire connector is rectangular in shape, with a small notch or indentation on the bottom edge of the connector shell. A 4-pin connector only carries data, and no power, so it is often found on peripherals that have their own power supplies.

To provide power and data transfer, the 6-pin FireWire connector is larger than the 4-pin, and is rectangular-shaped with beveled corners on one end. It has flattened contacts that withstand well the rigors of plugging and unplugging. A 6-pin interface provides DC power in addition to the Firewire data signals. These interfaces are often found on devices that can provide power, such as a computer.

9-pin connectors are part of a recent improvement to Firewire technology, called Firewire 800 (or IEEE-1394b) that can transfer data at up to twice the speed of the original Firewire standard. The 9-pin plug is a rectangle with square corners. It has 5 pin contacts on one side, and 4 pin contacts on the other. The entire plug is recessed within the shell of the connector.