This Gauge32 gives the finalized count of cells received with transport errors - HEC or uncorrectable FEC errors - during the previous 15-minute period. As a closed data point, it's what an NMS would chart alongside successive previous-period samples to establish whether downstream transport quality on this STU is improving or worsening over time. For example, comparing stuStatsPrevAtmTei across a week's worth of previous periods would show whether a plant repair actually reduced transport errors or whether the problem persists.