MIDI

The Musical Instrument DIgital Interface is a technical standard that describes a communications protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, computers, and related audio devices for playing, editing and recording music. The specification originates in a paper titled Universal Synthesizer Interface, published by Dave Smith and Chet Wood, then of Sequential Circuits, at the October 1981 Audio Engineering Society conference in New York City. Wikipedia