Eugene Goldstein developed cathode rays in 1876.
Sheldon Bidwell developed the telephography in 1880.
Paul Nipkow develpoed the electric telescope in 1881
The interdiction of vacum-tube amplification for telephone line allowed AT&T to experiment with sending speeches to distant audiences that listened over loud speakers. The next step would be to use the lines to radio stations, and in December 1921 a memo written by two AT&T engineers, J.F.Brantley and H.C.Lavender back outline the establishment of a national radio one work, financially supported by advertising.