The present disclosure relates to a galvanic isolation device or a bidirectional connecting line of a LIN bus system with two optocouplers arranged in antiparallel, each having a light-emitting element and a light-receiving element, wherein the galvanic isolation device is connectable to a LIN bus via a first signal connection and to a microprocessor via a second signal connection, wherein each signal connection is connected to the respective light-emitting element of an optocoupler, and wherein a diode is connected in antiparallel to the light-emitting element, such that, when a low signal level is applied to one of the signal connections, the signal level at the other signal connection is also low, without the signal being fed back.