Run the display interface transceiver verbose command to check the transmit and receive optical power of an optical module. In the command output, Current RX Power (dBm) and Current TX Power (dBm) indicate the current receive and transmit optical power of the. Have you ever encountered a Cisco switch interface that constantly flaps (goes up and down) or suddenly enters an err-disabled state? Before you blame the switch or replace the cable, you need to look at the invisible data: the light levels. Sample Output: IOS-router#show hw-module subslot 0/2 transceiver 2. Open in new tab to zoom. Transmit power is typically good when it is in the 6 dB range between -1 and -7 dBm. 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. By checking module health, compatibility, and digital diagnostics, you can quickly confirm correct installation, detect optical problems, and maintain accurate hardware inventory. Additionally, identifying module information helps detect coding.
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