A modular plug-in connector includes: at least one connection terminal; and a printed circuit board module housing which is connected to the at least one connection terminal. The printed circuit board module housing includes a recess for reversibly inserting a module printed circuit board, a voltage input terminal connectable to a voltage source, and a voltage supply contact that is electrically connected to the voltage input terminal. The module printed circuit board inserted in the recess is suppliable with electrical energy from the voltage input terminal vis-à-vis the voltage supply contact. The printed circuit board module housing includes a signal line terminal and a signal line contact electrically connected to the signal line terminal, such that data exchange between the signal line terminal and the module printed circuit board inserted into the recess occurs using the signal line contact.