HUI (Human User Interface)
More info
- Creator
- Mackie and Digidesign
- Released
- 1997
- Type
- Control surface and protocol
Mackie and Digidesign's 1997 control surface for Pro Tools, whose MIDI protocol outlived the hardware by more than two decades.
The box itself had eight motorised faders, transport buttons and a small display, and talked to the computer over ordinary MIDI cables. The protocol carves the surface into zones and ports: a button press becomes two controller messages, one selecting the zone and one saying which button it was and whether it went down or up. Fader positions travel as two 7-bit values stitched together into 14 bits.
The spec was never officially published, so third-party makers sniffed the cable and guessed. That didn't stop nearly every control surface from shipping a HUI mode anyway, because for years it was the only way to make Pro Tools listen. Its successor Mackie Control is cleaner and more capable, but HUI remains the lowest common denominator that refuses to die.