Use the DDMI screen (DDMI) to view the DDMI (Digital Diagnostics Monitoring Interface) status of the SFP transceivers on the Switch. 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. They connect switches, routers, and servers through fiber-optic or copper links, ensuring reliable communication between infrastructure layers. By checking module. 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.