For ABB i-bus® KNX External supply: 12-24 AC/DC Absorption: max 10 mA from the BUS. External supply to be sized for 3-W peak. Number of outputs: 1 bistable relay 4A @24V AC/DC. Number of inputs: 1 on the rear side, NO, max. connection length 10m. Ambient conditions: class 3k5 (indoor rooms and dry rooms). Relative humidity: max 90% (non condensating).