1394b extends speeds and distances

To further advance interconnections of computers, peripherals, and digital cameras, the Standards Board of the Institute of Electrical and Electronics Engineers Standards Association has approved IEEE Standard 1394b—High-Performance Serial Bus

To further advance interconnections of computers, peripherals, and digital cameras, the Standards Board of the Institute of Electrical and Electronics Engineers Standards Association (IEEE-SA; Piscataway, NJ;www.standards.ieee.org) has approved IEEE Standard 1394b—High-Performance Serial Bus—which amends the IEEE 1394-1995 and IEEE 1394a-2000 standards. The IEEE 1394b standard, often called FireWire or iLink, upgrades the prior standards by permitting gigabit signaling to 3.2 Gbits/s, extending signaling distances to 100 meters, and maintaining backward capability to the existing versions. It also complies with key features of the two earlier versions, such as point-to-point connectivity, plug-and-play changeability, and guaranteed timing. More important, for machine-vision, it will accommodate high-multimegapixel densities and increased color depths.

The IEEE 1394-1995 standard has been widely implemented, and many industrial and commercial vision and imaging products use its primary external interface. The IEEE 1394b standard expands the number and type of devices that can be connected and also supports a wider range of interconnect media, such as Category 5 unshielded twisted pairs and glass and plastic optical fibers. In addition, cable lengths have been extended to 50 meters for plastic-optical-fiber cables and to 100 meters for glass-optical-fiber cables. Moreover, 100-Mbit/s operation is supported over Category-5 wire to 100 meters, 200 Mbits/s over present plastic optical fiber and 400 Mbits/s over newer plastic optical fiber, and 3.2 Gbits/s over 50-µm multimode glass optical fiber.

Under the new amendment, high-speed serial buses can be integrated with most IEEE-standard 32- and 64-bit parallel buses to allow for easy interconnection among external peripherals. As for connectors, the new standard is fully operable with 1394a-2000 and 1394-1995 6- and 4-pin connectors. Bus speeds have been increased to 800 Mbits/s, 1.6 Gbits/s, with architectural support to 3.2 Gbits/s, and all can be transferred over copper wire.

Solid-state camera manufacturers are using the IEEE 1394 interface standard to replace conventional frame grabbers and save costs in machine-vision system designs, obtain plug-and-play interoperability, and network multiple cameras (see Vision Systems Design, April 2002, p. 29). For more information on development, compliance, and interoperability activities of 1394/FireWire, refer to the 1394 Trade Association (Grapevine, TX; www.1394ta.org).

George Kotelly
Editor in Chief
georgek@pennwell.com

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