IEEE 1394 is an interface standard for a serial bus for high-speed communications and isochronous real-time data transfer. It was developed in the late 1980s and early 1990s by Apple in cooperation with a number of companies, primarily Sony and Panasonic. It is most commonly known by the name FireWire (Apple), though other brand names exist such as i.LINK (Sony), and Lynx (Texas Instruments). Most consumer electronics manufacturers phased out IEEE 1394 from their product lines in the 2010s. The copper cable used in its most common implementation can be up to 4.5 m (15 ft) long. Power and data are carried over this cable, allowing devices with moderate power requirements to operate without a separate power supply. FireWire is also available in Cat 5 and optical fiber versions. The 1394 interface is comparable to USB. USB was developed subsequently and gained much greater market share. USB requires a host controller whereas IEEE 1394 is cooperatively managed by the connected devices.
History and development
FireWire is Apple's name for the IEEE 1394 High Speed Serial Bus. Its development was initiated by Apple in 1986, and developed by the IEEE P1394 Working Group, largely driven by contributions from Sony (102 patents), Apple (58 patents), Panasonic (46 patents), and Philips (43 patents), in addition to contributions made by engineers from LG Electronics, Toshiba, Hitachi, Canon, INMOS/SGS Thomson (now STMicroelectronics), and Texas Instruments. IEEE 1394 is a serial bus architecture for high-speed data transfer, serial meaning that information is transferred one bit at a time. Parallel buses utilize a number of different physical connections, and as such are usually more costly and typically heavier. IEEE 1394 fully supports both isochronous and asynchronous applications. Apple intended FireWire to be a serial replacement for the parallel SCSI bus, while providing connectivity for digital audio and video equipment. Apple's development began in the late 1980s, later presented to the Institute of Electrical and Electronics Engineers (IEEE), and was completed in January 1995. In 2007, IEEE 1394 was a composite of four documents: the original IEEE Std. 1394–1995, the IEEE Std. 1394a-2000 amendment, the IEEE Std. 1394b-2002 amendment, and the IEEE Std. 1394c-2006 amendment. On June 12, 2008, all these amendments as well as errata and some technical updates were incorporated into a superseding standard, IEEE Std. 1394–2008. Apple first included onboard FireWire in some of its 1999 Mac models (though it had been a build-to-order option on some Macintosh models since 1997), and most Apple Mac computers manufactured from 2000 through 2011 included FireWire ports. However, in February 2011, Apple introduced its first Mac with Thunderbolt, which superseded FireWire. Apple released its last computers with FireWire in 2012. By 2014, Thunderbolt had become a standard feature across Apple's entire line of computers (with some exceptions), effectively becoming the spiritual successor to FireWire in the Apple ecosystem. Apple's last Mac products with FireWire, the Apple Thunderbolt Display and 2012 13-inch MacBook Pro, were discontinued in 2016. Apple sold a Thunderbolt to FireWire adapter, with a single FireWire 800 port, until 2023. A separate adapter was required to use it with Thunderbolt 3. Sony's implementation of the system, i.LINK, used a smaller connector with only four signal conductors, omitting the two conductors that provide power for devices in favor of a separate power connector. This style was later added into the 1394a amendment. This port is sometimes labeled S100 or S400 to indicate speed in Mbit/s. The system was commonly used to connect data storage devices and DV (digital video) cameras, but was also popular in industrial systems for machine vision and professional audio systems. Many users preferred it over the more common USB 2.0 for its then greater effective speed and power distribution capabilities. Benchmarks show that the sustained data transfer rates are higher for FireWire than for USB 2.0, but lower than USB 3.0. Results are marked on Apple Mac OS X but more varied on Microsoft Windows.
Patent considerations Implementation of IEEE 1394 was said to require the use of 261 issued international patents held by 10 corporations. Use of these patents required licensing; use without license generally constituted patent infringement. A licensing administrator sub-licensed these patents to providers of equipment implementing IEEE 1394. Under the typical patent pool license, a royalty of US$0.25 per unit was payable by the manufacturer upon the manufacture of each 1394 finished product; no royalties were payable by users. Companies holding IEEE 1394 intellectual property formed a patent pool with MPEG LA as the license administrator, to whom they licensed patents. The last of the patents, MY 120654 by Sony, expired on November 30, 2020. As of that date, the following were patent holders of the IEEE 1394 standard, as listed in the patent pool then managed by MPEG LA, which has been defunct since 2023.
A person or company was able to review the actual 1394 Patent Portfolio License upon request to the licensing administrator. The licensing administrator did not provide assurance of protection to licensees beyond its own patents. At least one formerly licensed patent is known to have been removed from the pool, and other hardware patents exist that reference IEEE 1394. The 1394 High Performance Serial Bus Trade Association (the 1394 TA) was formed to aid the marketing of IEEE 1394. Its bylaws prohibit dealing with intellectual property issues. The 1394 Trade Association operates on an individual no cost membership basis to further enhancements to 1394 standards. The Trade Association also is the library source for all 1394 documentation and standards available.
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