A principle of modular synthesizer design that states that all signal interconnects should be electrically interchangeable (same signalling type, voltage range, etc.) and use the same type of connector. This allows audio and control signals to be freely intermixed. Many early modulars did not have unified patching; for instance, the 1970s PAiA modulars used banana jacks for control inputs and outputs, and 3.5mm phone jacks for audio signals. And vintage Moog modulars infamously used Cinch-Jones connectors and "open collector" outputs for gate and trigger signals. Buchla modulars to this day do not use unified patching.