This read-write setting configures the operating mode, such as inactive, dedicated, answer, or call-backup, for the WAN link on port 4, provided that port is configured with the PVCR protocol, during this schedule period, following the same pattern as the other schedulePort objects but for the unit's fourth such port. Since this entry has no distinct description text, its behavior is inferred from the shared enumeration and naming pattern across the series. For example, setting this object to inactive(1) during this period takes port 4's WAN link out of service for the duration of the scheduled window, independent of the other ports.