Heating and cooling sequence, - digital input for external operating mode switch, - 2-point control, - adjustable switching difference (1 K heating, 0.5 K cooling or 4 K heating, 2 K cooling), - input for return air temperature sensor (QAH11.1), - frost protection mode, - adjustable dead zone (2 K or 5 K), - outputs for 3-speed fan (0 / I / II / III)