Uninterruptible power supply 640 mA with integrated choke for supplying an ABB i-bus® KNX bus line, short-circuit- and overload-proof. LEDs to indicate the status of the bus current, mains voltage, and battery voltage. Wide range input from 85…265 V AC, 50/60 Hz. The power supply can charge the accumulator module AM/S 12.1 or up to 2 rechargeable batteries in normal operation. The bus voltage is provided utilising the batteries in the event of a mains failure.