To: Distribution From: David K. Kahaner Office of Naval Research Asia (From outside US): 23-17, 7-chome, Roppongi, Minato-ku, Tokyo 106 Japan (From within US): Unit 45002, APO AP 96337-0007 Tel: +81 3 3401-8924, Fax: +81 3 3403-9670 Email: kahaner@cs.titech.ac.jp Re: Japan's progress on ISDN 6 May 1992 This file is named "isdn.92" ABSTRACT. A summary of Japan's activities in ISDN, Integrated Services Digital Network. I have only written one short report on ISDN (May 9 1990, isdn) as it is outside of my expertise area, but I am consistently asked about it by Western scientists. The following has been prepared mostly by staff in the US Embassy, Tokyo. I have added detail and edited it down for electronic transmission. The important points here are that broad-band ISDN, high speed communication, is coming to Japan. Companies are preparing products for the time when, not if, this will be widely available.The actual date this reaches large numbers of Japan subscribers is less important than the sense that it is moving inexorably forward. (Now there are digital telephone boxes popping up in Tokyo, at least, with ISDN plugs for computer, fax, etc.) NTT is the major agent, and their monthly NTT Review is full of articles about applications. The current narrow-band integrated-services digital network (N-ISDN) went into operation in Japan in April 1988 with the implementation of NTT's INS Net-64, which has a 64kbit/sec transmission capability. In June 1989 NTT introduced INS Net-1500, with a much higher speed of 1.5Mbit/sec. INS Net-1500 allows multimedia communication, including teleconferencing, and it is possible to transmit a document page via fax in only three seconds. INS Net started with 29 users and 114 subscriber lines.Total INS Net-64/1500 subscriber lines have now passed the 60,000 mark. NTT claims that the number of ISDN circuits contracted for is expected to have reach 80,000 by April 1992, including about 2,000 areas in Japan. With a maximum transmission speed of 1.5Mbit/sec, N-ISDN service is limited to the transmission of voice, low- and medium-speed data, still pictures, and simple moving images. Broad-band ISDN (B-ISDN), with transmission speeds as high as 620Mbit/sec, will be able to handle high-density media such as high-definition television (HDTV), cable TV, and videotex. The asynchronous transfer mode (ATM) technique, key to B-ISDN switching, increases both speed and frequency bandwidth by a new transmission protocol.In N-ISDN, telephone, fax, video and TV signals are divided and passed through several different switching systems and then re-combined just before reaching the receiving terminals. ATM technology integrates these into a single net. The individual ATM transmitting terminal chops the information waves into cells of fixed lengths, assigns labels to them, and sends the "wavelets" to the net. When these cells arrive at the receiving end, the various information signals, grouped by assigned label, are directed to appropriate terminals: telephones, computers, or TV conference terminals. Although ISDN is still in the fledgling stage, Japanese industry is busy preparing for the second-generation B-ISDN, which is up to 2,000 times faster than the existing ISDN. In 1990, the International Telegraph and Telephone Consultative Committee (CCITT) introduced formal guidelines for B-ISDN. The Japanese telecommunications provider, NTT, plans to have B-ISDN operational for commercial users in 1996 with three distinct features: ATM net, optical-fiber communication, and "opticalization" of components. The new technologies will begin to replace the existing ISDN infrastructure around the year 2000, and is planned to be completed by 2015. It is claimed that optical-fiber will reach cost parity with copper by 1995. New 10Gbit/sec transmitting and receiving equipment is being developed by Toshiba for commercial availability in 1996. This equipment will use one optical fiber to carry 120K telephone lines simultaneously up to 80km. It will feature several gallium arsenide IC's capable of processing information, and claimed to be three to five times faster than conventional silicon IC's. NTT has also successfully carried out a 10- Gbit/sec optical transmission experiment using dispersion-shifted single- mode optical fibers with a combined length of 1,260km, which are installed in a commercial route between Tokyo and Hamamatsu (route length 326km). NTT's Large-Scale Integration (LSI) Laboratory recently introduced two new types of LSI chips for use with optical communications in B-ISDN. The FIFO (first in, first out) LSI chip is intended for ATM use, and the time-slot-converter LSI chip is designed for use in circuit divisions and multiplexing. The FIFO LSI chip uses 0.8mu BiCMOS technology on a single chip to upgrade processing speeds from the 8OMbit/sec of conventional FIFO to 25OMbit/sec, while reducing power consumption from 20W to 0.8W. The NTT system also involves an optical switching system based on VSTEP (vertical-to-surface-transmission electrophotonic device) technology, developed by them. The prototype switching system includes a superhigh-speed 4x4 (four inputs, four outputs) cell-fluting circuit that makes it possible to switch optical signals without converting them to electrical signals, and an optical buffer memory that holds input signals until they are placed on the output lines. NTT's experiments, said to be the first of their kind, verified the feasibility of high-speed optical throughput switching, required to achieve 1Tbit/sec ATM switching for B-ISDN. In the area of standardization, NTT has developed a B-ISDN quality standardization system called "SQUARE" (Subjective QUality Assessment REference system) capable of measuring and standardizing both sound and video quality through simulation. NTT is seeking to establish SQUARE as an international standard for B-ISDN quality control through the CCITT. Fujitsu has developed FLM2400, a synchronous digital hierarchy (SDH) optical telecommunications device for B-ISDN with a transmission speed of 2.4Gbit/sec. NTT also claims to be working in this area. SDH makes it possible to directly multiplex and cross-connect channels that have different capacities, allowing greater freedom and operational flexibility. In the B-ISDN-compatible terminals arena, Fujitsu has developed Monster, a multimedia workstation with a image processing capability, and has also announced a plan to produce an HDTV signal compression system within two or three years that would be able to vary transmission speeds over a B-ISDN line by 6OMbit/sec to 13OMbit/sec. Since HDTV signals require extremely high transmission rates (approaching 1Gbit/sec), the optical-fiber line over which the signals are sent can become too crowded for other data transmissions to take place concurrently. The ability to slow down the HDTV signals could provide an effective means of "time sharing" among various signals while reducing data loss or contamination, a major problem in high-speed ATM transmissions. ---------------------------END OF REPORT--------------------------