FireWire 1394, officially known as the Institute of Electrical and Electronics Engineers (IEEE) 1394, is a type of technology that allows users to transfer large amounts of computer data between devices. The FireWire 1394 also is called FireWire 400, because this cable is able to transfer up to 400 megabits per second (Mbit/s), though this speed may not be constant. IEEE 1394 is used to describe both the cable and port, which began as a six-circuit device but evolved into a four-circuit device. As a standard, the IEEE 1394 length is 15 feet (about 4.5 meters), but up to 16 cables can be linked together to increase the length. There have been some improvements on the 1394 design and, as of 2011, the FireWire 800 has been released and two other standards are planned.
Most consumers refer to the FireWire 1394 as the FireWire 400, because this reflects the cable’s transfer rate. Many devices are able to keep this speed constant, but some older devices may have lower transfer rates of around 100 to 200 Mbit/s. While this cable can be used to transfer small items, it is more commonly used to transfer large files such as an entire hard drive, games and movie files.
The FireWire 1394 standard is used to describe both the cable, which performs the data transfer, and the port that connects the cable between two or more devices. When the IEEE 1394 standard was first made in 1995, the cable head and port had a six-circuit connector. Later, the four-circuit connector was invented; it is considerably smaller than the six-circuit, but there is little difference in terms of performance.
As a standard, the FireWire 1394 cable length cannot exceed 15 feet (about 4.5 meters). To increase this length, users much connect one cable to another until the desired length is met. Only 16 cables can be used at once, or the data will not transfer properly.
Several improvements have been made in the original FireWire 1394 design to create faster transfer rates. The FireWire 800 is commercially available and can sustain maximum transfer rates of 800 Mbit/s. FireWire S1600 and S3200, which are in development as of October 2011, are expected to be able to transfer 1.6 gigabits a second (Gbit/s) and 3.2 Gbit/s, respectively. Minor improvements also have been made that do not increase transfer speed but enhance data streaming and decrease the amount of power required for a data transfer.