by an optical sender diode 4 is received by a photodiode 5 as infrared pulse packets these infrared pulse packets striking the photodiode 5 with a carrier frequency of 38 khz for example are converted into electrical current signals s in they are available at the input connector e of the receiver circuit 10 these electrical current signals sin are fed to an input circuit 11 working as a transimpedance amplifier which amplifies the current signals s in and converts them into voltage signals in the following signal processing component these voltage signals are amplified by a control amplifier 12 limited by a limiter 13 and then filtered in a bandpass filter 14 the signal limitation by means of the limiter 13 is required in order to avoid an overmodulation of the following bandpass filter 14 and to suppress pulse shaped interference entering the receiver via a supply connector v s for example the band pass filtered signal is demodulated in a demodulator 15 following the bandpass filter 14 buffered in an amplifier 16 with gain factor 1 and made available via an input and output circuit i o 21 at an output connector a as an output signal s out to a microcontroller 3 for further processing in order to optimize the amplification of the useful signal emitted by the sender diode 4 and thus the sensitivity of the receiver the receiver circuit 10 has a control circuit 25 which feeds the control signals to the control amplifier 12 and which for its part receives as input signals the output signal of the bandpass filter 14 via a line 71 and the output signal d out generated by the demodulator 15.