This Integer32 gives the finalized count of OAM cells the ComPort's voice port received during the previous 15-minute period, the closed-window counterpart to the current-period receive-OAM counter. Comparing this against the previous period's transmit-OAM counter lets an admin confirm the voice circuit's maintenance signaling was flowing in both directions during that completed window. For example, a previous period where stuVoiceChanStatsPrevTxOamCellCnt was nonzero but stuVoiceChanStatsPrevRxOamCellCnt was zero would indicate a one-way OAM signaling gap that already occurred on that line.