The closed switch is checked before the menu plays; the holiday list and the hours are checked after the caller picks a department. The whole path is on How the phone works.
Phone and messages
Opening hours and holidays
The three settings that decide whether a caller reaches a queue or the closed greeting, and who changes them
Three settings decide whether a caller reaches a queue or hears the closed greeting: the switch that closes the whole line, the holiday list, and each department’s weekly hours. All three live in the engine.