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. 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. Checking optical power helps pinpoint issues. This article provides instructions on how to view the Optical Module Status on your switch through the Command Line Interface (CLI). 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. 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. Here are the sample commands for checking the TX/RX optical power. Sample Output: IOS-router#show hw-module subslot 0/2 transceiver 2. For network engineers working with fiber optics (SFP, SFP+, QSFP), understanding TX (Transmit) and RX (Receive) signal strength is critical. Additionally, identifying module information helps detect coding.