An adapter configured to connect a switch device to a data bus, wherein the switch device has a box-like body which houses a switching unit for switching an electric circuit, wherein the adapter includes a case having a first opening and a second opening and an electronic control unit housed in the case and having a first connection element adapted to be connected to the switching unit through the first opening and second connection element adapted to be connected to the data bus through the second opening to convert the electric signals generated by the switching unit into data signals and vice versa.