FTTx common faults handling process: never been so specific!

  1. FTTH faults handling process

First step: check the status of ONT (fiber optic modem) “power” light.

(1). “No light” indicates abnormal electricity power supply. Need to check if the power connection and power adapter are working.

(2). “Long light” indicates normal power supply, turning to the second step.

Second step: check the status of ONT (fiber optic modem) “LOS” light.

(1). “No light” indicates normal signals, turning to the third step.

(2). “Flashing light” indicates the fiber optic modem do not receive the signals or lack of

sensitivity, turning to the fifth step.

Third step: check the status of ONT (fiber optic modem) “PON” or “ LINK” light.

(1). Long light, shows that ONT receives the signals of OLT, turning to the fourth step.

(2). Flashing light, shows that ONT receives light power that is lower or higher than the optical receiving sensitivity, ONT fails to register, turning to the fifth step.

(3). No light, shows ONT can’t receive the signal of OLT, turning to the fifth step.

Fourth step: check the status of ONT (fiber optic modem) “LAN” light.

(1). Flashing light, shows that fiber optic modem is normally connected with computer or users router, turning to the sixth step.

(2). No light, shows that the fiber optic modem is incorrectly connected with computer or users router, switch. Steps of detecting are as below:

  1. check if the network card of users is forbidden.
  2. use network cable tester to check if the network cables are working.
  3. replace the fiber optic modem LAN port or router, switch ports and then test if it is working. By this way, you can identify where the problem is.

Fifth step: check the light attenuation.

(1). check the performance of fiber optic modem receiving optical power by two methods: a. login to the fiber optic modem and check it.

  1. check it by the PON optical power meter. Remove the ONT (fiber optic modem) “PON” fiber pigtail access optical power meter (selecting the wavelength of 1490nm), test if the optical power is within the standard value (-8~ -28dB).

(2). Received optical power is too small and optical attenuation is too much. Check if the rubber-covered fiber optic cables between users and optical splitter box are bent or damaged.

(3). Check if the receiving optical power from the one of splitter ports is normal. If can, continue to test if the rubber-covered cable is working by using red laser pointer; if working, need to remake the fiber optic cable ends; if not working, replace with a new fiber optic cable. If the receiving optical power is not normal, then need to test the other splitter port to confirm if it can’t work; if it still works, need to replace the optical splitter ports; if not working, test the head uplink port of optical splitter.

(4). It is needed to do troubleshooting stage by stage from the second-stage ONU, the first-stage ONU and OLT’s PON port output when the uplink optical attenuation of the second-stage optical splitter is too much, which requires two technicians to finish this process.

Sixth step: Dial testing the users’ account.

Cut off the users’ router, connect directly to the laptop and dial. Common dialing error codes have:

(1). 691. Possible reasons:

  1. Account downtime: check if the phone is in arrearage. If so, inform the users of transact renewing.
  2. Wrong password: get the resetting broadband password of carrier.
  3. Account binding validation errors: call the backend technicians to handle.
  4. Account has already been online at another place: need the backend technicians clear the account in the system and then re-online.

(2). 678. It indicates broadband connection is cutoff. You need to check if the fiber optic modem signal is working. If working, call the backend technicians to check if the fiber optic modem data is normal.

(3). 769. This code indicates the user’s network card is forbidden. You need to re-enable the network card.

 

  1. FTTB faults handling process

First step: check the status of ONU “power” light and FE electrical port indicator light.

(1). Power light on, shows the power supply is working.

(2). Power light off, shows the power supply is not working. Check if there is a power failure or power breakdown.

(3). Right FE long light, shows the connection is working; off, shows no connection, turning to the second step.

(4). Left FE flashing light, shows there is data transmission.

Second step: check the status of interconnecting device like router “power” light and “WAN” light at user’s home.

(1). Power light on, shows the power supply is working.

(2). Power light off, shows the power supply is not working. Check if there is a power failure or power breakdown.

(3). WAN light on or flashing, shows the connection is working.

(4). WAN light off, shows failed connection, turning to the third step.

Third step: check if the ONU end ports are damaged. There are two ways to check it out.

(1). Use network cable and laptop to test if the ports are networking. If FE indicator light is off, the local connection of laptop is not available, which shows the ports are likely to be failed.

(2). Unbind the user’s account and replace the ONU ports to test. If it’s working, turning to the fourth step.

Fourth step: check the network cable.

Use network cable tester to check if the cable is working. If not, replace with a new one; if working, turning to the fifth step.

Fifth step: stand-along test at user’s home.

Remove the network cable from WAN port and connect it to the computer for single dialing test. If still working, it is likely that the issue is on the LAN or devices; if dialing not working, turning to the sixth step.

Sixth step: check the account error information.

For the error code 691, there are multiple possible reasons as below:

(1). Account downtime: check if the phone is in arrearage. If so, inform the users of transact renewing.

(2). Wrong password: get the resetting broadband password of carrier.

(3). Account binding validation errors: call the backend technicians to handle.

(4). Account has already been online at another place: need the backend technicians clear the account in the system and then re-online.

Conclusion

In the FTTx (FTTB/ FTTH/FTTC…) fiber optic broadband system, there are multi-stages fiber optic devices and cables involved for the connection and transmission. When faults happened, taking the correct, organized troubleshooting steps would be the most effective way for users to fix it. Besides, reaching out for a reputable FTTx fiber optics solution provider such as www.cozlink.com, is a cost-effectively solution for fixing any problem of the broadband or upgrading your network.

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