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 switch ( most of them 6500, 4500 and 4900) shows the ports for these servers as one gig connections. The dilemma here is to find out if these are ethernet connections & if they are fibre, are their any SFP's connected on the port. What i understand is if the interface shows 10/100/1000 TX - it. 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. This guide gives a practical, CLI-focused workflow for checking SFP health and diagnostics on Cisco switches, shows the exact commands you'll use, explains what the numbers mean, and compares OEM (Cisco) vs third-party modules so you can pick the right SFP module supplier for reliability and cost. By checking module health, compatibility, and digital diagnostics, you can quickly confirm correct installation, detect optical problems, and maintain accurate hardware inventory. This guide provides complete, step-by-step CLI commands to view module type, DOM/DDM diagnostic data.