The ICF-1170I Series CAN-to-fiber converters are used to convert CAN signals from copper to optical fiber. The converters come with 2 kV optical isolation for the CAN bus system and dual power inputs with alarm contact relay to ensure that your CAN bus system will remain online. Fiber Test Mode Fiber Test Mode can be used to test the fiber cable between two ICF-1170I units, and it provides a simple way to determine if the fiber cable is transmitting data correctly. When in Fiber Test Mode, the fiber transceiver (Tx) will continuously send out a data signal and the Fiber Tx LED will light up. On the other side of the connection, when the ICF-1170I fiber transceiver (Rx) receives the data signal from the Tx side, the Fiber Rx LED will light up.