Abstract: In a data-transmission system designed for operation over a very broad temperature range and having a very large dynamic range, the receiver is of the type providing an alternating-current connection between the transimpedance circuit assembly and two comparator circuits for processing a signal which is coded at three levels. A threshold-generating circuit permits automatic switching of the thresholds among a plurality of predetermined discrete values as a function of the variation in amplitude of the signal. A circuit for inhibiting overoscillations is provided prior to transcoding. The transmitter delivers the information in the form of an internal code such as a PBP code having a constant direct-current component, and with refreshment. A delay circuit prevents overlapping of the code and refreshment pulses.