Abstract: In a transponder (1) and an integrated circuit (5), the integrated circuit (6) has a monitoring circuit (23) to which a d.c. supply voltage (VS) can be fed and by which a signalizing signal (POK) whose waveform is dependent on the relationship between the d.c. supply voltage (VS) and a voltage threshold value (VTHR1, VTHR2) can be generated, wherein the monitoring circuit (23) is arranged to be controllable in respect of the generation of the signalizing signal (POK), and wherein a control circuit (28) is provided for controlling the monitoring circuit (23) by means of at least one control signal (CS1, CS2).