Abstract: A process and a device for increasing interference suppression, especially in optical proximity switches, with an optical transmitter emitting an optical pulse train (1), an optical receiver emitting a measuring signal (2) and a control and evaluation unit controlling the optical transmitter and evaluating measuring signal (2), in which the measuring signal (2) of the optical receiver includes a superposition of a constantly emitted interference background (4) and a measuring pulse (6) emitted when receiving an optical pulse (5), and in which the measuring signal (2) of the optical receiver is evaluated by the control and evaluation unit in a signal interval (8) during a measuring pulse (6) and in at least one background interval (9) outside measuring pulse (6). The increase of the interference suppression is assured in that the evaluation is interrupted by gaps (11, 12) before and after the signal intervals (8) or background intervals (9).