A modular electronic and/or electric apparatus including a plurality of circuit units connected by an internal communication bus. The circuit unit includes at least two serial resistor elements forming a voltage divider. The resistor elements of the circuit units are serially connected and form an ID wire. The ID wire is interconnected between a first voltage terminal and a second voltage terminal. The circuit unit comprises at least one analog-digital converter. A connection point between two resistor elements of one circuit unit is connected to an analog input terminal of the analog-digital converter. A digital output terminal of the analog-digital converter is connected to the internal communication bus. The modular electronic and/or electric apparatus includes a master unit connected to the internal communication bus. In particular, the present invention relates to a modular domestic appliance including a plurality of circuit units connected by an internal communication bus.