A term originally applied to Vari-lite fixtures, but since expanded to all moving lights. Short for "calibration," and known on some fixtures/consoles as "home," "reset," or "initialization." All motors are exercised, limits are discovered, and then the fixtures does what the console is telling it to do, or, if no DMX is present, goes to its default values. Synonymous with soft-reset. The most recent generation of fixtures allow for calibration of just one IFCB system, rather than all of them at once. All fixtures will cal when power is first applied. This is why you see them "doing their dance" before they'll listen to the console. On older fixtures (Intellabeams, Cyberlights, etc.), if the lamp is not lit, the cal command will also LampON the fixture. A good practice is to recal all fixtures at the start of each programming session, and before each show.