Eurorack is a shared electrical standard (12V power, ±10V signals) that lets modules interconnect and 'talk to each other'

Eurorack is not only a physical form-factor but an electrical standard. Per the project’s About Eurorack page, modules are about 5 inches tall, run off 12-volt power, and output ±10V signals; they must fit the same case, draw from the same power supply, and output the same range of voltages ‘so they can talk to each other.’ Because every module speaks the same voltage language, one module’s output can drive another’s input regardless of what each does — a clock can trigger an envelope, a random source can feed a quantizer, and so on. This shared standard is what makes modular synthesis freely patchable, distinguishing it from fixed-architecture synths where the signal path is hard-wired. (Pitch CV conventionally uses 1V/octave, though the specific standard is set per module — the Quantizer here works on ‘1V/oct control voltages.’)

Examples

A freemodular Clock outputs gate/trigger pulses that can drive any other module’s trigger input; the RNG’s random CV can feed the Quantizer, whose output drives an oscillator’s 1V/oct pitch input — all interoperating because they share the same voltage ranges and power.

Assessment

Explain what it means that Eurorack modules ‘talk to each other,’ citing the power voltage and signal range. Why can a module’s output drive an unrelated module’s input? What is the 1V/octave convention used for?