... 155M optical interface flexible optional, support optical ring network topology with redundancy dual-network.l Over 20km optical transmission distance, 155Mb/s ... , ring, and other network structure, multi-mode fiber 0~2Km, single-mode fiber 0~20Km, more remote optional, optical interface type: ST ... Industrial fieldbus Protocol CAN bus/CAN open/DeviceNet fiber optic modem with double LAN Ci-af22-m