The arrival phase of the Optical Network Unit (ONU)
transmission may drift due to aging, temperature changes and
other factors. In those cases, the equalization delay can be
recalculated/updated from the drift of the upstream
transmission. This allows small corrections to be made without
having to re-range the ONU.
Configuration parameters in this grouping govern ONU
upstream transmission phase drift monitoring by an Optical
Line Termination (OLT).