Musical Instrument Device Interface, or MIDI, was a standard created in the 1980s for electronic transport of musical data. Since then it has been adapted to a wide variety of uses, including the triggering of lighting control systems.
Several ETC lighting products have featured MIDI connections. Typically lighting consoles can be triggered by MIDI (e.g. Cue 1 go), and some can have individual button hits fired by MIDI. Consoles may also be able to output MIDI.
Physical Connections
MIDI uses 5 pin DIN connectors to connect between equipment. Any piece of equipment may have up to three MIDI connections :
- MIDI In : The console receives MIDI through this connector
- MIDI Thru : As multiple devices may be daisychained in MIDI systems, this can be used to link the MIDI control signal through to other systems. This is typically a direct link or direct opto-isolated link from MIDI In.
- MIDI Out : For devices capable of controlling other MIDI devices, this connector is where the controlled devices are connected.
MIDI Concepts
In ETC products, there are three main types of MIDI control that may be implemented :
- MIDI Show Control (MSC)
- MIDI Time Code
- MIDI Notes
The way MIDI is implemented on your controller depends on what product you have; you should look at the specifications or manual for your console for details.
MIDI Show Control (MSC)
MIDI Show Control provides a method for transmitting show-control type messages (e.g. "Cue 1 GO") over MIDI.
In a show control system a triggering device, usually a sequencer running on a computer, sends commands which trigger the lighting system.
MIDI Time Code
MIDI Time Code provides a method of clock synchronisation, similar to SMPTE time code, but running over MIDI hardware.
MIDI Notes
Originally developed as a protocol for controlling individual musical instruments, MIDI has support for notes. Notes are used in some consoles to provide, in effect, remote key presses on the console keys (e.g. pressing the GO button), or fader moves.
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