Abstract: A elevator door protection system, having an infrared curtain comprising pairs of infrared transmitters and receivers and circuitry responsive to an output of the receiver due to interception for opening the elevator doors, includes detection circuitry which responds (a) when the elevator doors are closed, so as to reduce the usual power supplied to the transmitters; and (b) when the elevator doors open, so as to restore the usual power to the transmitters. Preferably, a time delay is included so that power dissipation is reduced only after a predetermined period following door closure. The invention reduces power consumption of infrared transmitter diodes, hence extending their lifetime.