This OCTET STRING holds the upper optical-power bound above which the OLT raises an alarm for an ONU's transceiver, flagging a receive signal that is unusually strong rather than weak. Admins set this because an abnormally high Rx power on an ONU often indicates a wiring or splitter-loss-budget mistake, such as too short a fiber run or a missing attenuator, that can eventually damage the receiver. For example, an upper threshold near -3 dBm flags an ONU receiving a signal that strong, prompting a check of the splitter configuration on that leg before it causes long-term optic degradation.