The present disclosure relates to a fan motor control device comprising a control signal input for applying a rotational speed control voltage as the control signal input signal and a control signal output for picking off a control signal output signal for connecting to a fan motor, where modulation means are connected downstream from the control signal input, said modulation means being designed to convert the control signal input signal into a digital and/or pulsed modulation input signal, and isolated transmission means are connected downstream therefrom, which transfer the digital and/or pulsed modulation input signal into a digital and/or pulsed modulation output signal isolated from the control signal input, which is converted into the control signal output signal that can be picked off on the control signal output by means of demodulation means connected downstream from the transmission means.