The approach relates to a procedure for determining a signal transmission quality of a light transmission path, which consists of a light transmitter on one end and a light receiver on its other end. A transmitter code is received in a first step. The transmitter code hereby represents a signal which is transmitted from the light transmitter to the light receiver. In a further step the receiver code is read in. The receiver code hereby represents a signal which was provided by the light receiver by using the transmitter code. The determining of a degree of correspondency between the transmitter code and the receiver code is performed in a final step of determining, in order to define the signal transmission quality of the light transmission path.