A method for communication, intended in particular for the purpose of a configuration, calibration, parameterization, interrogation or even a test or diagnosis, between a master device and a slave product including at least a processing unit and a direct current power supply line or input, and, if necessary, at least one output line and/or output interface. The method includes transmitting to the product data that can be interpreted by the processing unit thereof, the data being transmitted via the power supply line and by modulating the supply voltage.