Print PageA. Christian Jacobaeus, 1911 -
Christian Jacobaeus' name is linked closely with the theory and practical application of the crossbar switching system which dominated the post-World War II technical development of telephone exchanges. During a 40-year career dedicated to the advancement of telecommunications technology Dr. Jacobaeus laid down the principal building blocks for the LM Ericsson Telephone Company crossbar system which represented a major breakthrough for Ericsson on the world market and which today is standard equipment in many countries. Born in Stockholm in 1911 Dr. Jacobaeus spent his entire professional career with LM Ericsson and for more than two decades directed Ericsson's worldwide technical and research activities. His personal scientific and innovative contributions to telephony and his technical leadership and vision in initiating and guiding research and development programs were instrumental in the rapid growth of Ericsson over the past quarter-century. His pioneering research into dimensioning in switching systems led to a completely new discipline in the field of traffic theory which facilitated the accurate computation of blocking in link systems and optimized the design of switching matrices. In his doctoral thesis, published in 1950, he set down in principle and detail what has since become the standard work on congestion in link systems throughout the telecommunications industry. The firm theoretical foundation he laid down accelerated the development and introduction of crossbar technology, at least outside the U .S., by making the crossbar switch economically attractive as a building block for switching systems. He also developed practical methods of implementing crossbar systems, including techniques for path search and control. Dr. Jacobaeus' technical leadership and initiative were the driving forces not only in the field of crossbar technology but also in the development of electronic switching systems, notably in the area of time division multiplexing. His efforts resulted in such achievements as the first usable electronic switching systems for the U .S. Air Force and the development of stored program controlled systems at LM Ericsson. Dr. Jacobaeus joined Ericsson in 1935 as a sales and project engineer for signaling equipment a year after receiving his M.S.E.E. degree from the Royal Institute of Technology in Stockholm. In 1939 he was transferred to the telephone switching department where he was a sales and project engineer and, later, a systems engineer. He was appointed chief of the research department in 1950, a year in which he also received his doctorate in electrical engineering from the Royal Institute of Technology. Three years later he was elected vice president and chief technical officer of LM Ericsson and, in 1959, executive vice president. Since his retirement in 1976 he has served as a consultant to the management of LM Ericsson. Dr. Jacobaeus holds over 30 patents in the field of telephony and has published numerous papers on telecommunications subjects. He was one of the founders of the first International Teletraffic Congress in 1955 and has since been active in the steering group for these congresses, which have contributed importantly to the development of telecommunications traffic theory. A member of the Swedish Academy of Engineering Sciences since 1957 and its vice chairman during 1969- 71 he was the recipient of the Academy's Major Gold Medal in 1976. He was elected a member of the Royal Swedish Academy of Sciences in 1974 and has been a Fellow of the IEEE since 1977. He has served on a number of governmental technical committees over the years and in 1978 received an honorary Doctor of Electrical Engineering degree from the University of Lund in Sweden. Dr. Jacobaeus, who resides in Stockholm, travels extensively and enjoys reading and bridge. His other interests include golf and boating. His wife, Irene, is an administrative assistant at the International Federation of Institutes of Advanced Study which coordinates international research projects. His daughter, Antonia, a former exchange student in the U.S., is studying medicine in Sweden. Dr. Jacobaeus won the 1979 Alexander Graham Bell Medal "For pioneering work in the theory of switching systems and technical leadership in the development of telecommunication systems." From the 1979 IEEE Awards Reception Brochure |
