THE IQ21X SERIES OF INTELLIGENT CONTROLLERS ARE DESIGNED FOR USE AS UNITARY CONTROLLERS IN BUILDING CONTROL SYSTEMS. FULL COMPATIBILITY WITH OTHER TREND IQ CONTROLLERS ENABLES THE IQ21X TO INTEGRATE THE LOCAL ENVIRONMENTAL NEEDS WITH THE BULK AIR CONDITIONING SYSTEM IN ORDER TO OPTIMISE BOTH COMFORT AND RUNNING COSTS. THE CONTROLLERS HAVE 5 INPUTS AND 6 OUTPUTS. THE IQ211 HAS 6 TRIAC OUTPUTS; AND THE IQ212 HAS 4 TRIAC OUTPUTS AND TWO 0 TO 10 V OUTPUT