A monitoring device (6,10) monitors the functioning of a reporting system (1). The reporting system (1) includes a plurality of reporting devices (4) and/or signaling devices, supply lines (3), and a voltage source. The reporting devices (4) and/or signaling devices are connected to the voltage source via the supply lines (3), and the reporting devices (4) and/or signaling devices are connected in parallel to one another and to the voltage source. A test signal device (6) connects a reference resistor (R) into the supply lines (3) in parallel with the reporting devices (4) and/or signaling devices, and/or connects the reference resistor (R) as a termination of the supply lines (3). An evaluation device (10) detects and evaluates the system response of the reporting system (1) to the connecting of the reference resistor (R).