The invention relates to a method for the transmission of a digital signal in inverse multiplexing, particularly via an Optical Transport Network (OTN), in which a digital signal to be transmitted, which is split into a certain number M of several sub-signals, where each sub-signal of a transmit side of a transmission line assigned exclusively to this sub-signal is transmitted to a reception side of the assigned transmission line, and in which, on the reception side of the transmission lines, the sub-signals are reassembled to a digital reception signal. According to the invention, on the reception side, bit errors in the digital reception signal including their position in the digital reception signal are detected, and from the detected position of the bit errors and from the assignment of the individual bytes of the digital reception signal to the respective sub-signals and transmission lines, which assignment is also known on the reception side, it is determined to which sub-signal the detected bit errors were assigned. From this one or more parameters are determined, which characterize the transmission quality of the transmission lines assigned to each sub-signal and/or allow inferences to be drawn regarding which error mechanisms of the transmission line in question impact its transmission quality. In addition, the invention relates to a reception device for a system for the transmission of a digital signal in inverse multiplexing, which carries out this method.