PURPOSE: To provide a connector having a broken wire detection frequency while reducing the number of interconnection wires interconnecting a stationary part and a moving part in an automation equipment.

CONSTITUTION: A master station 2 arranged in a stationary part 12 and a slave station 4 arranged to a moving part 13 are respectively provided with a conversion circuit A10 and a conversion circuit B14 converting an electric digital signal into an optical serial signal or vice versa to implement 2-way communication and the stationary part 12 and the moving part 13 are tied by an optical cable 3 to reduce the number of interconnection wires, and a broken wire between the stationary part 12 and the moving part 13 is attained by measuring a luminous quantity of the optical serial signal.