How does China Unicom open the SMS reminder service for the other party?

Power-on reminder means that when you call a called user who is turned off or out of service area, you will receive a short message reminder that the called user is turned on after the called user normally turns on or returns to service area. If local support, you can apply to your own business hall with valid documents: the startup reminder service in some areas has stopped ordering, and users who have ordered can still use and cancel normally.