Abnormality recovery system

摘要

An abnormality recovery system in a network comprising a plurality of station units connected by a ring-like data transmission line enabling circular transmission of communication data in digital form in a single direction. In the system, when it is determined that an abnormality occurs in a communication IC, a CPU performs switch control to switch a communication data route so as to bypass the communication IC and send communication data on a bypass from an optical receiver to an optical transmitter.