The KNX IO 546.1 secure (1D1O) is a compact dimming/switching actuator with one dimming output for active electronic ballasts, a 0/1-10 V interface, and one bistable relay output. The dimming actuator can be used for various active electronic ballasts, such as LED panels or strips. Each configuration allows channel control via switching, relay dimming, and dimming value. Various comfort functions are also integrated, including scenes, night fade, staircase lighting, and a sequencer. The device optionally supports KNX Security.

The switching actuator offers universal output functions, including scene control, timers, staircase lighting, and heating valves (PWM for thermoelectric valve drives). Two buttons and three LEDs allow local control and display of the device status. In addition to the output channels, the device includes 16 independent functions for logic or time-based control.