CMTS Status Event List definitions for Cable and Broadband Technicians. Learn about the CMTS event list and how it can help you understand CMTS status lists Secondary Channel MDD timeout QAM/FEC lock failure Sequence out of range MDD recovery QAM/FEC lock recovery T4 timeout T3 re-tries exceeded Successful ranging after T3 re-tries exceeded CM operating on battery backup CM returned to A/C power MAC Removal Event DS OFDM profile failure Primary Downstream Change DPD Mismatch Invalid DPD NCP Profile Failure Loss of FEC Lock on PLC NCP Profile