The Harry F. Olson papers include schematics and drawings, a body of articles and patents, and correspondence from Olson’s work in acoustics at various RCA research divisions.

Photographs include, predominantly black and white with a few color, images of loudspeakers, microphones, and the magnetic video tape recording system.

Sound tape reels contain over 40 recordings of 'word lists' presumably used by Olson in his work with the phonetic typewriter.

The Herbert Belar papers are composed of schematics, notes, and compositions from Belar’s work on acoustical electronics, including a music composing machine, a phonetic typewriter, and the music synthesizer, at RCA Laboratories, from 1943 to 1967. They also include schematics and reports on several projects Belar did for the military during World War II as part of a secret RCA working group called “MAD Lab.” Of special note is a 1955 letter from Robert Moog, then a student at Queens College, requesting information on RCA’s electronic music synthesizer.

Thirty-seven of Belar's lab notebooks (1948-1966) can be found in Record group 26.

The Telecommunications series contains images of equipment, components, parts, and details. The series is arranged into six subseries: Equipment, Facsimile equipment, Mobile, Speech, Telephones, and TELEX. The materials date from 1930 to 1977.