Kitahara Yasusada was born in 1914 and graduated from Waseda University in 1940 and earned Ph.D. degree from the university for his contribution to the research of coaxial cable .

He joined the ministry of post and telecommunication in 1940 and moved to Nippon Telegraph and Telephone Public Corporation in 1953. He held prominent positions such as director of the Kyushu Telecommunication Bureau in 1963, director general of Plant Engineering Bureau in 1965, senior managing director in 1970 , chief engineer in 1974 and vice president in 1977.

He devoted his first half of his career to the restoration of the telephone networks in Japan destroyed by the war and the latter half to the enhancement of the networks as the top technical leader of NTT. NTT succeeded in clearing the backlog of telephone subscription in 1978 and realizing the nationwide direct dialing in 1979.

His biggest contribution to the computer industry was the proposal and commercialization. of data communication service by NTT as early as in 1960's.

He led NTT to launch the data communication service as the third service of NTT after the telegraph and the telephone. The first data communication service of NTT was provided to Gumma Bank and the association of local banks in Japan in 1968. NTT expanded the service to such areas as finance and public administration and the business unit for the service was separated from NTT in 1990 as NTT Data Corporation.

Moreover, he examined the management of telecom service providers at the post telephone age and proposed to deploy the new services such as the fax and data communications and to digitalize the telecom networks for those purposes.

This concept was first announced to the public at the world computer conference in 1978, and at the world telecommunication forum in 1979. He proposed to provide voice, video and data communication services all in digital form with the common tariff using the ISDN networks. This business concept was dubbed as Information Network Systems and got everyone’s attention at the above conferences.

To concretize his concept NTT implemented an INS prototype system in Miataka city in 1984 and demonstrated the plants and the various applications there. He led NTT to lauch the first ISDN service in the world in 1988.

Kitahara stepped down from the vice president of NTT in 1988 and served as a member of Council for Science and Technology and a chairman of a committee for telecom and broadcast cooperation. He passed away in 1994.

He served as the President of the Institute of Electronic, Information and Communication Engineers of Japan in 1976 and the senate of the Japan-China Center for science, technology and culture. in 1990. He won the many distinctions, which include the Prize from the NTT president, Maejima Award, the commendation by the Minister of State for Science and Technology, Special Award for Industrial Technologies from Mainichishinbun, Achievement Award/ Contribution Award/ Honorary member from IEICE, Honorary Professor from Beijin University of Posts and Telecommunications and IEEE fellow.