What makes the picture talk: AT&T and the development of sound motion picture technology

The development of technological system that brought sound to motion pictures in the 1920s at AT&T´s Bell Laboratories and its predecessor, the Western Electric Engineering Department, is described. The telephone company had set out to perfect the national telephone network. Among the technologies developed in this effort were amplifiers, loud speaking telephones (i.e. loudspeakers), condenser microphones, and electrical sound recording and reproduction. In 1922, all the pieces necessary for the addition of sound to movies were in place except for a means to synchronize sound and picture, a task then given to a team of engineers. By 1924, AT&T has produced a complete working system. Western Electric established a subsidiary in 1927 to work with the motion picture industry to develop commercial sound film production, and with the theater owners to equip thousands of theaters to show sound films