Why does the mobile phone automatically switch to SMS?

This is the case when the phone is turned off or the other party's phone has no signal and an incoming call reminder is turned on.

Someone who calls a mobile phone, is out of service area or turns off his phone, will notify him by SMS.

The other party should call you back when they see your call reminder message.

Extended data

Incoming call reminder refers to saving all incoming call information for you within 24 hours through the incoming call reminder platform when the mobile phone is turned off or out of service area. After the mobile phone returns to normal, all incoming information will be sent to your mobile phone in the form of SMS, so that you will no longer worry about losing important calls!

remind

1. Customers cannot use the call reminder service when setting up call forwarding, but they can use the call reminder after canceling the call forwarding setting.

2. After the call reminder is turned on, when the mobile phone is turned off or out of service area, the message a friend hears when making a call is "Call reminder reminds you that the subscriber you dialed can't be connected for the time being, thank you for using it, please hang up", and he doesn't need to pay for it.

3. The short message recording the incoming call information is kept in the system for 24 hours.

References:

Call Reminder-Baidu Encyclopedia