The KNX power supply 640 mA with diagnostic function and extended LED display generates and monitors the KNX system voltage (SELV). The integrated choke decouples the bus line from the power supply. The voltage output is short-circuit-proof and overload-proof. The two-color LED shows the status of the device. The device has an additional short-circuit-proof and overload-proof 30 V DC voltage output. This can be used to power another bus line (in conjunction with a separate choke). The power supply has a wide-range input for the supply voltage in the range 85.265 V AC, 50/60 Hz.