The invention relates to a sensor (10), comprising at least one transducer (12) for transmitting signals and receiving reflected echo signals, which transducer is designed to output an analog measurement signal (101), an analog-to-digital converter (22) for converting the analog measurement signal (101, 102) into a digital measurement signal (104), an evaluating unit (30) for evaluating the digital measurement signal (104) and a communication unit (40) for transmitting a measurement result (110) of the evaluation via a digital communication interface, the communication unit (40) being designedto receive a request (52) for diagnostic data (54) via the digital communication interface and also being designed to switch the sensor (10) to diagnostic operation and to transmit requested diagnostic data (54) via the digital communication interface, characterized in that the communication unit (40) is designed to communicate via the digital communication interface with at least two different data rates, a higher data rate being used for the transmitting of the diagnostic data (54) than for transmitting of the measurement result (110) in normal operation of the sensor (10). The invention further relates to a system, comprising a control unit and at least one of the described sensors (10).