If the optical module is faulty, replace it with the spare part. If the optical module is installed on a GE port, run the display interfaceGigabitEthernet x/x/x command to view port information when the optical module. Based on typical issues encountered with optical modules in daily switch applications, this document summarizes basic troubleshooting steps for resolving common faults: 1. Check compatibility between the optical module and switch Most switch brands have specific compatibility requirements. The Cisco Small Business Series Switches allow you to plug in a Small Form-factor Pluggable (SFP) transceiver in their optical modules to connect fiber-optic cables. Once the transceiver and fiber optic cable are plugged in properly in the switch optical module, the Optical Module Status page of. This kind of fault mainly includes port not up, port status up but not receiving or sending messages, frequent up or down port and CRC errors. The following summarizes the main reasons and solutions in the event of failure.