A system composed of a servicing device and a field device having at least one sensor unit for determining and/or monitoring at least one process variable. At least one electronics unit, which has an evaluation unit, wherein the evaluation unit receives measurement signals from the sensor unit and evaluates such with reference to the process variable, and at least one switch element actuatable contactlessly from outside of the field device. The servicing device is embodied to modulate the switch state of the switch element for transmission of field device specific data to the electronics unit. Furthermore, a field device, a servicing device and a method for communication between field device and servicing device are claimed.