If your router does not display a fiber optic connection, the issue may stem from physical connections, device compatibility, or configuration errors.

Check Physical Connections

Ensure that the fiber optic cable is properly connected to the Optical Network Terminal (ONT) and that the ONT is powered on. Inspect the fiber cable for visible damage, sharp bends, or loose connectors, and clean the connectors with lint-free wipes and isopropyl alcohol to remove dust or oil, which can block the signal .

Verify Device Compatibility

Confirm that your router supports fiber connections. Some routers require an SFP port or a WAN port labeled for fiber or ONT input. If your router is not fiber-ready, it may not detect the connection even if the ONT is functioning .

Connect ONT to Router

Use a high-quality Ethernet cable (Cat6a or higher) to connect the ONT's Ethernet/LAN port to your router's WAN port. Power on the router and wait for the indicator lights to stabilize. A spinning or red light may indicate a failed connection or negotiation issue .

Check Network Configuration

• If your ISP provides a static IP, ensure the router is configured with the correct IP address, subnet mask, gateway, and DNS servers.
• If using dynamic IP, enable auto-detection in the router settings. Some routers may default to dynamic IP even if static IP is configured, which can prevent connection .
• For certain ISPs, you may need to enter VLAN ID or account credentials in the router's configuration interface to establish a connection .

Test and Troubleshoot

• Swap the Ethernet cable or router port to rule out hardware issues.
• Restart both the ONT and router to clear temporary glitches.
• If the connection still fails, test the ONT directly with a computer to verify that the ISP is providing an active signal .

When to Contact Your ISP

If all physical connections and configurations are correct but the router still does not detect the fiber connection, the issue may be on the ISP's end, such as a misconfigured ONT or service activation problem . Contact your ISP to confirm that your fiber service is active and properly provisioned. By systematically checking cables, device compatibility, configuration settings, and ISP activation, you can identify the root cause and restore your fiber optic connection to the router.