ONT LOPL LOA

Description

Declared when the PON card does not receive an acknowledge from the ONT after sending a set of downstream messages requiring an upstream acknowledgment. This alarm should not happen under normal operating scenarios and typically indicates that the ONT is not responding to OMCI messages. This could indicate that the ONT is too busy to respond or has failed. ONTs that exhibit this alarm should be examined for Bit Errors occurring on the ONTs in the ONT Status Tab > Properties display.

ONTs experience a few BIP errors during startup and reboot operations, but during normal operations should remain, for the most part, error free, as long as the ONT optics (fiber plant, lasers, and optical budget, are within specifications.

Laser Safety

Warning! Personnel handling fiber optic cables must be trained for laser safety.

Warning! Optical Fibers emit invisible laser radiation. Avoid direct exposure to the beam. Never look into the end of a Fiber or into a Fiber connector on a cable or a device. Permanent eye damage or blindness can occur quickly from laser radiation.

Fiber Optic Cable

Ensure that the fiber connectors are properly cleaned per local standards. Dirty connectors may result in inaccurate measurements.

Caution: Fiber optic cable installation and maintenance should only be performed by trained service personnel.

Caution:  Do not bend the fiber optic cable to a diameter smaller than 7.5cm/3 inches. Doing so may damage the fiber or prevent the signal from passing through properly.

Trouble Clearing

The probable causes of this alarm are: 

• Dirty Fiber: Dirt and debris on the fiber connectors can cause this alarm. Ensure that all connectors are properly cleaned and maintained. Fibers should be cleaned prior to each insertion.
• Bend in Fiber: If the bend radius in the fiber exceeds the recommended bend radius of the fiber it is possible for this alarm to occur. Ensure that no fibers exceed the recommended minimum bend radius or possibly have a bend or have been closed in an enclosure door.
• Rogue ONT: It is possible that one ONT on the fiber, that is transmitting outside its transmission window, can possible affect other ONTs. If multiple ONTs are experiencing LOPL-LOA alarms, this may indicate a rogue ONT on the PON. Typically, the rogue ONT experiences LOPL-LCD (refer to ONT LOPL LCD) and LOPL-LOA alarms.
• eStop ONTs: It may be possible to locate the rogue ONT by eStopping the alarmed ONTs on the PON to isolate which is causing the problem.
• Replace Alarmed ONTs: It may be possible to resolve the alarm by replacing the alarmed ONTs, starting with the ONT which is experiencing LOPL-LCD.

If none of the troubleshooting steps above resolve the issue, refer this alarm to Tellabs Technical Assistance Center (refer to Contacting Technical Support).