This read-write enabled/disabled flag controls whether the PDU sends an SNMP trap to the configured trap receiver for a branch circuit's voltage dropping to a warning-level low reading. Enabling it lets a centralized SNMP monitoring system, such as IPNetwork Monitor, raise the alert automatically the instant it happens rather than waiting for the next scheduled poll. For example, when a branch circuit's voltage dropping to a warning-level low reading actually happens on this unit, an NMS like IPNetwork Monitor receiving the trap and immediately raising an alert on its dashboard is exactly the effect this setting produces.