Abstract: A circuit in which driver units are associated with data networks that are coupled through at least two single transmission channels is provided. The driver units have a logical signal input and a logical signal output on their sides facing away from the data network, with the signal input or signal output of one driver unit being connected with the signal output or signal input of the other driver unit through a signal transmission channel in each case for coupling each of two data networks. A logical coupling control unit is looped into the coupling signal transmission channels. The unit blocks the signal path to the other signal transmission channel when predetermined blocking signal information appears on one signal transmission channel. This ensures that feedback and oscillation effects are suppressed during the transmission of signals over the transmission channels. The circuit can be used for coupling CAN data networks in motor vehicles.

Abstract: In a data communication system, in particular for a motor vehicle, the transmission lines that lead to the individual terminals are interconnected at a passive network in a star configuration and are there provided with frequency-dependent attenuation means, preferably ferrite beads. Good characteristic impedance adaptation is thus obtained for suppressing high-frequency distributing signals, while retaining free choice of the system parameters for the steady data symbolic state. The system may be enlarged by means of additional star networks into a tree or meshed structure.