1# Common Events of the Time and Time Zone Subsystem 2This document lists the common system events provided by the time and time zone subsystem to applications. Applications can use [APIs](../js-apis-commonEventManager.md) to subscribe to common system events. 3 4## COMMON_EVENT_TIME_CHANGED 5Indicates that the system time has been set. 6 7- Value: usual.event.TIME_CHANGED 8- Required subscriber permissions: none 9 10When the system time is set, the event notification service is triggered to publish this event. 11 12## COMMON_EVENT_TIME_TICK 13Indicates that the system time has changed. 14 15- Value: usual.event.TIME_TICK 16- Required subscriber permissions: none 17 18On devices where the unit of time is minutes, when the system time changes, the event notification service is triggered to publish this event. 19 20## COMMON_EVENT_TIMEZONE_CHANGED 21Indicates that the system time zone has changed. 22 23- Value: usual.event.TIMEZONE_CHANGED 24- Required subscriber permissions: none 25 26When the system time zone changes, the event notification service is triggered to publish this event. 27