Lee de Forest’s Sale of Audion Rights to AT&T and Its Importance for the Development of Radio Technics

The preparation and holding of the presentation of Lee de Forest’s audion, which contributed to the sale of his patent rights to AT&T, is considered. The role of J. Carty and John S. Stone in the presentation was noted. Harold D. Arnold’s experiments with the audion and Hendrik van der Bijl’s audion theory set the stage for industrial production of vacuum triodes for telephone repeaters. It is shown that the industrial production of a thermionic three-electrode vacuum tube has made it possible to develop innovative commercial telephone repeaters and achieve progress in long-distance telephony.