Sharp, Sony Eye 1394 Transmission Method For Portables
By Yoshiko Hara, EE Times Sharp Corp. and Sony Corp. have agreed to develop a compact transmission method compliant with IEEE 1394 and intended for use in portable digital consumer products. The companies plan to propose the format to related industries by year's end. Sharp and Sony's 1394 transmission method consists of a cable with a single plastic fiber, a compact plastic-optical-fiber (POF) transceiver module and a minijack. Sony will provide the 1394 technology it calls i.Link, and Sharp will supply technology related to its widely used Optical Mini Jack. The P1394b extension, which will extend transmission distance beyond the 4.5 meters of the current 1394 spec, is currently wending its way toward standardization. The POF for P1394b will use twisted-pair fibers. Seven companies, including Sony, proposed in June a new Small Multimedia Interface connector for the P1394b, which is about half the size of currently available PN-type POF connectors measuring 20.3 x 22.7 x 8.5 mm. This configuration is still too big for consumer products, said a Sony engineer. Over 10 Meters Sharp and Sony intend to propose a cable with a single plastic fiber instead of a twisted pair. The prototype fiber is 1 mm in diameter with a 980-micron core. Using inexpensive fiber, Sharp and Sony claim their transmission method enables full-duplex communication at more than 100 Mbits/second at a distance of more than 10 meters. The prototype connector and transceiver module are based on Sharp's Optical Mini Jack, launched in 1992. It is 3.5 mm in diameter and 15 mm long, almost the same size as a stereo minijack, and is used for one-way digital audio signal transmission. The single-fiber cable and the minijack will provide almost the same ease of use as current audio/video connections, said the Sony engineer. The method will provide 1394 links within a room; room-to-room connection may be possible via a P1394b network, he said. ""We'll develop a POF minijack based on the Optical Mini Jack, but final specifications have not been nailed down,"" said the engineer. Sharp and Sony plan to finalize specs by the end of the year and intend to propose them to other companies. The companies demonstrated their prototypes at the recent Japan Electronics Show 1999 in Makuhari, near Tokyo. Source: EE Times, www.eet.com