Log in to the switch console to run the privileged EXEC mode of the Cisco switch, use the fiber-ports-optical-transceiver command. The Output Power (mWatt) field in the command output indicates the received power of the optical module, and the Input Power (mWatt) field indicates the. 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. Monitoring the optical power of SFP (Small Form-factor Pluggable) modules is a critical step in maintaining stable network links. Even if an interface appears up, degraded Tx/Rx levels can cause intermittent flapping, packet loss, or err-disabled states. Here are the sample commands for checking the TX/RX optical power. Sample Output: IOS-router#show hw-module subslot 0/2 transceiver 2. Some switches like Cisco, Hpe, Brocade will offer CLI (Command-Line Interface) reference for users to view SFP modules DDM/DOM information, which includes transceiver temperature, the supply voltage in the transceiver, laser bias current, RX power TX power (mW or µW or dBm).
