When was the Scottish-born scientist died after whose invention "Kōbushō" had started an effort to make telephone receivers?
Oki Kibatarō Oki Kibatarō (沖 牙太郎 , 1848–1906) was an engineer formerly employed at a Japanese Ministry of Industry ("Kōbushō") factory. In 1877, only a year after Alexander Graham Bell's invention, "Kōbushō" had started an effort to make telephone receivers by reverse engineering and Oki was in the team that came up with the first prototype.
George Ashley Campbell George Ashley Campbell (November 27, 1870 – November 10, 1954) was an American engineer. He was pioneer in developing and applying quantitative mathematical methods to the problems of long-distance telegraphy and telephony. His most important contributions were to the theory and implementation of the use of loading coils and the first wave filters designed to what was to become known as the image method. Both these areas of work resulted in important economic advantages for the American Telephone and Telegraph Company (AT&T).