This read-only value reports whether an ONU PON port's SFP transceiver optical parameter is above the upper alarm limit, below the lower alarm limit, or back to normal, as carried in this NMS EPON trap. An admin uses this trap to catch an optical power or other SFP parameter excursion on the ONU's PON transceiver before it causes a service-affecting link failure. For example, receiving a trap with this object set to above(1) would prompt the admin to check that ONU's optical transmit power, which may be running hotter than expected.