Produced by Bell Labs in 1973, The Far Sound looks at the latest developments it telephony, electronics, and computers. The intro has Peter Max-ish graphics and a song that sounds like a Partridge Family instrumental.
1973, the year this film was made, was a very exciting time to be at Bell Labs. Telstar was under development. BellComm was about to be spun off, to work with NASA on the moon project. Technologies involving the transistor, laser, and the solar cell were underway. Scientists were just starting to explore what a computer was and what it might accomplish. In the middle of this wave of innovation was the Bell System's core business—providing telephone service to almost the entire country.
At 9:43, we get a great description of how transistors work, complete with anthropomorphic electrons.