A modular synthesizer format which falls into the "small format" category. Originally derived from various standards for 19" rack system based industrial and lab instrumentation known as (DIN 41494 / IEC 297-3 / IEEE 1001.1) and sometimes housed 'Eurocard' technology. Not to be confusedor with the line of low-cost mixers marketed by Behringer under this name. The Eurorack format calls for modules of 128.5mm (slightly over 5") height. Horizontal width is measured in "horizontal pitch", where 1 HP = 5.08mm (exactly 0.2"). 3.5mm mono phone jacks are used for interconnection.
The Eurorack format calls for ±12V power (most other current formats use ±15V), in addition +5V is required by some modules. Unfortunately, the orientation of the power connections are not well standardized; the format uses ribbon cables for power and a two-row ribbon cable connector containing either 10 or 16 pins. A "red stripe" on the ribbon indicates -12V. The 16-pin connector uses the extra pins to distribute +5V, control voltage and gate signals from a keyboard to the modules via a common case connection.
Manufacturers using the Eurorack format include Doepfer, Analogue Systems, MFB, Cwejman, Mutable Instruments , and River in Europe, and Make Noise, Intellijel, Plan B, Livewire, and Harvestman in the North America.