This read-write enabled/disabled flag controls whether the PDU generates a notification when another PDU expected to be part of its daisy chain link goes missing. An admin managing chained PDUs enables this to be alerted immediately if a unit drops off the chain, which could indicate a cable fault, power loss, or hardware failure on that unit. For example, if one PDU in a 4-unit chain loses network connectivity, the surviving units would flag it as missing rather than the gap going unnoticed.