An apparatus configured for an insertion of a cassette comprises at least one distance sensor operably measuring in a contactless manner a distance from a corresponding location on the apparatus to the inserted cassette. An electronic evaluator is operably connected to the at least one distance sensor to receive at least one distance signal corresponding to distances measured by at least one distance sensor, such that the electronic evaluator generates a position signal, resulting from the at least one distance signal, which is dependent on a dimension and a position of the inserted cassette in the apparatus. A control unit is operably connected to the electronic evaluator such that the control unit receives the position signal from the electronic evaluator.