In the Privileged EXEC mode of the switch, use the show fiber-ports-optical-transceiver command by entering the following: l interface interface-id - (Optional) Specify an Ethernet port ID. Note: In this example, te1/0/3 interface is used. Port - The port number on. 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. When optical modules operate on a switch, it is usually necessary to read the module's internal information to understand its working status—such as connection status and real-time metrics like optical power and temperature. Additionally, identifying module information helps detect coding. Digital Optical Monitoring (DOM) is a feature that allows for the real-time monitoring of various physical and operational parameters of fiber optic transceivers, such as transmit power, receive power, temperature, laser bias current, and voltage. DOM is supported on MS120, MS125, MS130, MS210. This guide provides complete, step-by-step CLI commands to view module type, DOM/DDM diagnostic data, vendor details, and compatibility information, fully compliant with Cisco IOS and IOS-XE command standards. Physical inspection: Start by visually inspecting the fiber ports on the switch. Look for any physical damage, such as bent or broken connectors, loose cables, or dirt/dust accumulation.