Call forwarding to call reminder service opened

Call reminder means that the smart call reminder service has been started. If the other party's mobile phone is turned off, it will receive a call reminder message after it is turned on, which is a very practical function.

Mobile phone card installation problem

Cell phone shows no signal. Maybe the mobile phone card is not installed, so you can take it out and reinstall it. If the mobile phone card is not installed incorrectly, you can enter the system settings page, find the flight mode option in the settings, turn on the flight mode, and then turn it off after a few seconds.

The line is busy.

The mobile phone prompts "the number you dialed is busy", which may be that the other party is answering the phone, so you can call again later; It may be that the other party is not convenient to answer the phone at the moment.

Sim card

SIM card of mobile phone is also called subscriber identity card and smart card. GSM digital mobile phone can only use this card. The information of digital mobile phone customers, encryption keys and user phone book are stored on the computer chip, which can be used to authenticate the identity of GSM network customers and encrypt voice information when customers talk.