The system performs communication between two systems, a master system, that creates an alternating magnetic field by means of which it dialogues with one or more slave systems, which respond at frequencies other than those generated by the master by a non-linear magnetic core generating harmonics of higher order than those of the magnetic field created by the master. The generation of harmonics is controlled by the slave by a short-circuit coil which enables the data transmission from the slave to the master. The slave system can have its own power supply or it can be powered by the short-circuit coil. This allows microcontrollers in the slaves to be powered and give them intelligence and a large storage capacity, making them ideal for control security and monitoring processes. The excitation frequency can be varied because the functionality of the slaves does not depend on the frequency of the exciter field.