Urgent feature reminder
From Zenitel Wiki
Urgent feature reminder (UFR) is a special type of alert tone which is activated when a station receives an Alarm Call Request (or any other mail) with priority level 120 or more. By default the Call Request code 622 has priority level 140, and thus activates "urgent feature reminder" at the receiving station.
By default the alert tone is a dut-dut-dut-dut tone repeated three times. Then 20 seconds pause, and the sequence is repeated again. The number of repeatitions and the pause is configurable from AlphaPro, Exchange & System -> System -> Calls and Options: 'Urgent Feature Reminder'.
See also Feature reminder