In the early days of the analog synthesizer, there was no practical way to communicate between electronic instruments. Syncing one synth to another involved a lot of guess-and-check: listening carefully and waiting for beats to match up. Overtime, manufacturers like Korg, Roland, and Sequential Circuits began developing systems that would allow their products to interface with one another. These systems were far from perfect: the Control Voltage / Gate (CV / Gate) method, arguably the most successful, was still typically reduced to changing two parameters of a sound: its pitch and duration. A single MIDI link, by contrast, can carry information to as many as 16 separate devices. Or, better put, the MIDI link transmits information between these devices. Whereas CV/Gate could only tell an instrument when to play which note for how long, a MIDI event message can specify the individual velocities, amplitudes, channel dominance, and much more for at least 24 notes simultaneously.

MIDI was dubbed the “open system” at least a decade before software would be termed "open source"

Jim Scott and Bob Moog (pronounced like “rogue”) took the first sizable whack at building a universal-synthesizer control system with the creation of the Micromoog in 1975. To keep their goal reasonable, the duo focused their energies on making sure the Micromoog could interface with only the products in their manufacturing line before tackling the quandaries involved in establishing communication between all makes and models. This Moog Instrument Digital Interface was dubbed the “open system,” at least a decade before software would be termed “open source.” In his typical, fashion, Moog describes the “open system” through the eyes of the audio-engineering oracle.