Anton Christian Jacobæus (1911 in

Stockholm, Sweden Stockholm () is the capital and largest city of Sweden as well as the largest urban area in Scandinavia. Approximately 980,000 people live in the municipality, with 1.6 million in the urban area, and 2.4 million in the metropoli ...

–1988) was a Swedish

electrical engineer Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...

, known for his contributions to

teletraffic engineering Teletraffic engineering, telecommunications traffic engineering, or just traffic engineering when in context, is the application of transportation traffic engineering theory to telecommunications. Teletraffic engineers use their knowledge of stat ...

, especially in the design of the modern

crossbar switch In electronics and telecommunications, a crossbar switch (cross-point switch, matrix switch) is a collection of switches arranged in a matrix configuration. A crossbar switch has multiple input and output lines that form a crossed pattern of int ...

used for

telephone switch telephone exchange, telephone switch, or central office is a telecommunications system used in the public switched telephone network (PSTN) or in large enterprises. It interconnects telephone subscriber lines or virtual circuits of digital syste ...

ing. Jacobæus graduated from the

Royal Institute of Technology The KTH Royal Institute of Technology ( sv, Kungliga Tekniska högskolan, lit=Royal Institute of Technology), abbreviated KTH, is a public research university in Stockholm, Sweden. KTH conducts research and education in engineering and technolo ...

(KTH) in 1933 with a

master's degree A master's degree (from Latin ) is an academic degree awarded by universities or colleges upon completion of a course of study demonstrating mastery or a high-order overview of a specific field of study or area of professional practice.

in electrical engineering. In 1935 he went to work for

L. M. Ericsson (lit. "Telephone Stock Company of LM Ericsson"), commonly known as Ericsson, is a Sweden, Swedish multinational networking and telecommunications company headquartered in Stockholm. The company sells infrastructure, software, and services in ...

, where he would spend his entire professional career. In 1950 he received his

doctorate A doctorate (from Latin ''docere'', "to teach"), doctor's degree (from Latin ''doctor'', "teacher"), or doctoral degree is an academic degree awarded by universities and some other educational institutions, derived from the ancient formalism ''l ...

in electrical engineering, also from KTH. His dissertation entitled ''A study of congestion in link systems'' became instrumental in the efficient design of crossbar switches. He became technical director in 1950, then senior

vice president A vice president, also director in British English, is an officer in government or business who is below the president (chief executive officer) in rank. It can also refer to executive vice presidents, signifying that the vice president is on t ...

from 1963 until his retirement in 1976. He then continued to serve as a

consultant A consultant (from la, consultare "to deliberate") is a professional (also known as ''expert'', ''specialist'', see variations of meaning below) who provides advice and other purposeful activities in an area of specialization. Consulting servic ...

to the company's management. He was a member of the

Royal Swedish Academy of Engineering Sciences The Royal Swedish Academy of Engineering Sciences or ''Kungliga Ingenjörsvetenskapsakademien'' (IVA), founded on 24 October 1919 by King Gustaf V, is one of the royal academies in Sweden. The academy is an independent organisation, which promo ...

1957–88, serving as its vice

chairman The chairperson, also chairman, chairwoman or chair, is the presiding officer of an organized group such as a board, committee, or deliberative assembly. The person holding the office, who is typically elected or appointed by members of the grou ...

1979–81, and a member of the

Royal Swedish Academy of Sciences The Royal Swedish Academy of Sciences ( sv, Kungliga Vetenskapsakademien) is one of the Swedish Royal Academies, royal academies of Sweden. Founded on 2 June 1739, it is an independent, non-governmental scientific organization that takes special ...

from 1974. He was a fellow of

IEEE The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operation ...

from 1977. In 1979, he was awarded the

IEEE Alexander Graham Bell Medal The IEEE Alexander Graham Bell Medal is an award honoring ''"exceptional contributions to communications and networking sciences and engineering"'' in the field of telecommunications. The medal is one of the highest honors awarded by the Instit ...

.Jacobæus' bio at IEEE History Center
(1979) Christian Jacobæus was the son of Hans Christian Jacobæus.

References

{{DEFAULTSORT:Jacobaeus, Christian 20th-century Swedish engineers Swedish electrical engineers Queueing theorists Ericsson people Members of the Royal Swedish Academy of Sciences Members of the Royal Swedish Academy of Engineering Sciences Fellow Members of the IEEE Engineers from Stockholm KTH Royal Institute of Technology alumni 1911 births 1988 deaths