A power controller for a DC-powered device , hereinafter DC-powered-device controller, comprising: - a DC-power unit configured to be electrically connected to an external DC-power supply device and to receive electrical DC-power of different power amounts therefrom; characterised in that - a DC-voltage monitoring unit configured to monitor a currently received voltage amount of the received DC-power (V PSD ), and to output a respective response signal indicative of the currently received voltage amount falling into a respective one of a number of predetermined non-overlapping voltage intervals including a mark-event-voltage interval (V M ) and an operating voltage interval (Vo), wherein voltage amounts of the mark-event voltage interval are lower than those of the operating-voltage interval; - a mark-event timer unit configured to receive the currently received response signal and to start a mark-event time measurement upon detecting that the currently received response signal indicates that the voltage amount of the currently received DC-power has made a transition into the mark-event voltage interval, and to provide an extended-mark-time signal upon detecting that a measured mark-event time since the start of the mark-event time measurement exceeds a predetermined mark-event duration threshold (Δt th ); - a control unit connected with the DC-power unit and configured to receive the current response signal and the extended-mark-time signal, and configured to enable delivery of the currently received DC-power to an external electrical load unit in event of either one of: a) detecting that the current response signal is indicative of the currently received voltage amount falling into the operating voltage interval, and b) detecting that the extended-mark-time signal has been received. - a DC-power unit configured to be electrically connected to an external DC-power supply device and to receive electrical DC-power of different power amounts therefrom; characterised in that - a DC-voltage monitoring unit configured to monitor a currently received voltage amount of the received DC-power (V PSD ), and to output a respective response signal indicative of the currently received voltage amount falling into a respective one of a number of predetermined non-overlapping voltage intervals including a mark-event-voltage interval (V M ) and an operating voltage interval (Vo), wherein voltage amounts of the mark-event voltage interval are lower than those of the operating-voltage interval; - a mark-event timer unit configured to receive the currently received response signal and to start a mark-event time measurement upon detecting that the currently received response signal indicates that the voltage amount of the currently received DC-power has made a transition into the mark-event voltage interval, and to provide an extended-mark-time signal upon detecting that a measured mark-event time since the start of the mark-event time measurement exceeds a predetermined mark-event duration threshold (Δt th ); - a control unit connected with the DC-power unit and configured to receive the current response signal and the extended-mark-time signal, and configured to enable delivery of the currently received DC-power to an external electrical load unit in event of either one of: a) detecting that the current response signal is indicative of the currently received voltage amount falling into the operating voltage interval, and b) detecting that the extended-mark-time signal has been received. a) detecting that the current response signal is indicative of the currently received voltage amount falling into the operating voltage interval, and b) detecting that the extended-mark-time signal has been received. <EOS>