My mobile phone doesn't have caller ID, and some numbers can't be recognized, but some will tell you the phone number by text message, saying1873550 * * * to call you, please reply in time.

First of all, SMS reminder is a "full-time communication" service of China Mobile. As long as your mobile phone is turned off and no one else's phone is connected, the system will automatically send a message to remind you.

Secondly, all mobile phones have caller ID. The call you received didn't show the number, it was set by the other party. One is PHS, which can be set in many areas and does not display numbers. Then there is the public telephone, especially the telephone supermarket opened by Unicom users, which generally does not display the number. Finally, there is another kind, that is, overseas areas, including Hong Kong, and many countries and regions, call home without displaying the number.