Patent ID: 8001306

Claim:
An interface unit for a communication system comprising a master unit and a plurality of slave units serially connecting the master unit via a double ring structure comprising a first communication path and a second communication path, the first transmission path comprising a first transmission line and the second transmission path comprising a second transmission line, the interface unit comprising a first switching unit, which is configured to output information signals received by the master unit as a first information signal to the first communication path and as a second information signal to the second communication path, and a second switching unit, which is configured to forward the first information signal circulating on the first communication path and second information signal circulating on the second communication path to the master unit, wherein an input of the first switching unit is connected to a transmitting unit of the master unit, a first output of the first switching unit is directly connected to the first transmission line of the first communication path and a second output of the first switching unit is directly connected to the second transmission line of the second communication path, and wherein a first input of the second switching unit is directly connected to the first transmission line of the first communication path, a second input of the second communication path is directly connected to the second transmission line of the second communication path and an output of the second switching unit is connected to a receiving unit of the master unit.