Execute the following command to view detailed interface and optical module status: show interface <interface-type> <interface-number>Execute the following command to view detailed interface and optical module status: show interface <interface-type> <interface-number>The following introduces the specific operations to view the working status and internal information of an optical module on a Cisco switch. This guide uses the Moduletek SFP-25G-SR optical module connected to a Cisco C9300 switch as an example. By checking module health, compatibility, and digital diagnostics, you can quickly confirm correct installation, detect optical problems, and maintain accurate hardware. If you run fiber or copper uplinks in a small office, home lab, or data closet, SFPs (and SFP+) are the little parts that keep your links alive. This guide gives a practical, CLI-focused workflow for checking SFP health and diagnostics on Cisco switches, shows the exact commands you'll use. Most brands' ethernet switches provide features to show interface transceiver details information via CLI (Command-Line Interface). Generally, you can use those commands to view specific transceiver vendor names, types, wavelength, distance, Serial Number, Part Number, and DDM/DOM parameters.
