Interbus is a sensor/actuator bus with low configuration expenditure. The summation frame protocol of this master/slave system offers high efficiency in cyclic communication. The typical topology is a line structure with branches, physically based on the RS485 standard. Distances of up to 400 m are possible at a data transmission rate of 500 KB; an expansion of up to 13 km can be achieved using repeaters. The maximum number of devices is limited to 256.