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Server optical module indicator lights

Server optical module LEDs indicate link status, activity, speed, and faults, with colors and blinking patterns providing diagnostic information.LED Colors and Meanings
  • Off: No link is present or the module is inactive .
  • Green, steady: The optical module is active and the link is established .
  • Green, blinking: Traffic is present on the active link, indicating data transmission .
  • Amber, steady: The link is operating at less than maximum speed (e.g., 100 Mbps or 1 Gbps) or a component is in a degraded state .
  • Amber, blinking: A critical fault is detected, such as a failed module, over-temperature condition, or other non-recoverable errors .
Diagnostic Information

Many servers and network devices allow you to view detailed optical module diagnostics using commands. For example, on Huawei devices, you can run:

  • display transceiver [interface interface-type interface-number | slot slot-id] to view module information.
  • display transceiver diagnosis interface [interface-type interface-number] to check digital diagnostic monitoring (DMM) data, including optical power, voltage, current, and temperature . These diagnostics help identify issues such as low or high optical power, faulty modules, or non-certified modules that may cause data bus errors or physical damage to the interface .
Practical Tips
  • Ensure the optical module is certified for your device to avoid compatibility and performance issues .
  • Check the LED patterns regularly to monitor link activity and detect faults early.
  • Use the server or switch management interface to correlate LED status with module diagnostics for precise troubleshooting.
  • Replace modules showing amber blinking or abnormal readings to prevent network disruptions . By understanding the LED indicators and using diagnostic commands, you can maintain optimal performance and quickly identify issues with server optical modules.
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Technical note

This reference is intended for preliminary specialty-cable research. Compatibility, link budgets, fire performance, installation methods, test limits and applicable standards must be verified for the specific project.

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