Can the FX120 PON Meter Indicate if an ONT is Rogue?

What is the significance of each ONT Status reported on FX120? Why it is Important?

The FX120 can report three different ONT status, registered, unregistered or rogue.

  1. As we all know, when an ONT status indicates Registered, this means that the ONT/ONU serial number was acknowledged by the OLT port (aka PON-ID) to be a valid SN so the activation process can continue through the remaining steps. This means that communication between the ONT and OLT was established and continues, and the activation process can resume until the OLT and ONT are both in sync.
  2. When an ONT status indicates Unregistered, the ONT is an unknown or Alien device. The common reason for this is that the ONT does not belong on this PON-ID. Some examples of this might be if a technician were to connect an EPON ONT or an XGS-PON ONU with a GPON OLT; or if your ONT SN was never registered to this PON-ID. In these types of situations, the OLT will send a message that it does not recognize this ONT SN and will request the ONT to deactivate itself.
  3. A Rogue ONT is when a registered ONT transmits outside of the OLT allocated transmission time slot either intermittently or continuously. This can happen when an ONT is defective or even simply overheated. This causes the ONT transmission to collide with other registered ONTs transmission on the same PON-ID who are keeping within their timeslot, resulting in transmission errors. Frequently, a customer with a rogue ONT does not even have service issues but other ONTs on the same PON-ID are very likely to report service issues. The most accurate way to find a Rogue ONT is to connect at that Rogue ONT site and monitor upstream traffic. However, since our FX120 only reports downstream communication, we can only report an ONT as rogue if the OLT detects rogue signals from a specific ONT and sends a deactivation message to the rogue device.