How did the RCA Electronic Music Synthesizer use perforated paper rolls?

The RCA Electronic Music Synthesizer utilized perforated paper rolls as an information input mechanism to control the creation of sound. Composers used a special typewriter-like keyboard to punch instructions into the paper tape, which served as the "master score" for a composition.123

The perforations encoded various musical properties—including pitch, tone color, vibrato intensity, envelope shapes, and portamento—in binary form for four simultaneous tones. These specifications were recorded for every 1/30 of a second, allowing composers to achieve a level of precision and speed in musical changes that exceeded the capabilities of traditional performers. During the programming process, composers could interrupt the activity to listen to the encoded material, make corrections, and edit the score before finalizing the tape.31