Fiber optic cable turns red

A red LOS (Loss of Signal) light on a fiber optic router indicates that the router is not receiving a proper signal from your Internet Service Provider (ISP).Common CausesPhysical Damage to the Fiber Cable Fiber optic cables are delicate and can be disrupted by cuts, bends, or kinks. Damage can occur during construction, severe weather, or accidental digging, which prevents light signals from reaching your router .Loose or Faulty Connections Improperly connected cables or damaged connectors can interrupt the signal. Even a slightly loose fiber connector can trigger the LOS light .ISP Service Outages Maintenance or local outages at your ISP can temporarily cut off the signal, causing the LOS light to turn red .Router or ONT Malfunction The optical receiver inside your router or Optical Network Terminal (ONT) may fail due to overheating, electrical surges, or hardware defects, preventing it from detecting the incoming signal .Environmental Factors Extreme temperatures, moisture, or dust accumulation can affect the router or fiber connections, leading to intermittent signal loss .Troubleshooting StepsCheck for ISP Outages Visit your ISP's website or social media pages to see if there is a known service disruption .Inspect Fiber Cables and Connections Look for visible damage, sharp bends, or loose connectors. Ensure the fiber cable is properly seated in the router's WAN/ONT port .Reboot Your Router Turn off the router, unplug it from the power source for 30 seconds, then reconnect and power it on. This can often restore the signal .Check Router Placement and Ventilation Ensure the router is not overheating by placing it in a well-ventilated area and cleaning dust from vents .Test or Replace Hardware If the LOS light persists, test the router or ONT with a known-good unit, or contact your ISP to check the optical power levels and replace faulty equipment if necessary .When to Call Your ISPIf the LOS light remains red after checking cables, rebooting, and ensuring proper router placement, the issue may be outside your home, such as a damaged fiber line or a problem at the ISP's hub. Contact your ISP for professional diagnostics and repair . By systematically checking these factors, you can often identify the cause of the red LOS light and restore your fiber optic connection.