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FireWire

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(Redirected from IEEE 1394 interface)

IEEE 1394 Interface
Type Serial
Production history
Designer Apple (1394a/b), IEEE P1394 Working Group, Sony, Panasonic, etc.
Designed 1986; 40 years ago (1986)[1]
Standardized January 1995; 31 years ago (1995-01)
Manufacturer Various
Produced 1994–current
Superseded by Thunderbolt, USB 3.0 and SAS
General specifications
Length 4.5 m (15 ft) maximum
Width 1
Hot pluggable Yes
Daisy chain Yes, up to 63 devices
Audio signal Yes (software encoding)
Video signal Yes (software encoding)
Pins 4, 6, 9
Electrical
Max. voltage 30 V
Max. current 1.5 A
Data
Data signal Yes
Bitrate
  • 1394a, half-duplex 100–400 Mbit/s (12.5–50 MB/s)
  • 1394b and later, full-duplex 800–3200 Mbit/s (100–400 MB/s)

FireWire 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 Apple name FireWire, but also referred to by the Sony name i.LINK and the Texas Instruments name Lynx. Most consumer electronics manufacturers phased it out in the 2010s. The standard is also adopted by the IEEE as IEEE 1394.

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.[2]

History and development

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The 6-conductor and 4-conductor alpha FireWire 400 socket
A 9-pin FireWire 800 connector
The alternative Ethernet-style cabling used by 1394c
4-conductor (left) and 6-conductor (right) FireWire 400 alpha connectors
A PCI expansion card that contains four FireWire 400 connectors
A FireWire 800 ExpressCard

FireWire is Apple's name for the IEEE 1394 High Speed Serial Bus. Its development was initiated by Apple[1] in 1986,[3] 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,[4] INMOS/SGS Thomson (now STMicroelectronics),[5] and Texas Instruments.

FireWire 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.[6] 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),[7] 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.[8]

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.[9] 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.[7] 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.[10][11]

Patent considerations

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Implementation of IEEE 1394[12] was said to require the use of 261 issued international patents[4] held by 10[5] corporations. Use of these patents required licensing; use without license generally constituted patent infringement.[13] 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;[13] 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,[4] which has been defunct since 2023.

Company Total patents
Sony 102
Apple 58
Panasonic 46
Philips 43
LG 11
Toshiba 10
Hitachi 4
Canon 1
Compaq 1
Samsung 1

A person or company was able to review the actual 1394 Patent Portfolio License upon request to the licensing administrator.[14] 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,[4] and other hardware patents exist that reference IEEE 1394.