Mobile Service: What is Peer-to-Peer SMS? What's the difference between call reminder and caller ID?

Hello, peer-to-peer SMS means that one mobile phone number sends a message to another. Call reminder means that when the customer's mobile phone is turned off or disconnected (in the basement/elevator), the call will be transferred to the voice response system to record the call number. After the mobile phone is turned on or returned to normal, the incoming call information will be sent to the customer's mobile phone by SMS. Caller ID service means that when you make a call from a normal domestic number (except international calls from Hong Kong, Macao and Taiwan), you can automatically display the calling number by using caller ID service, and you can freely know whether to answer it. For your reference, thank you for choosing China Mobile.