UIM (user? Identity? Model) user identification module is a mobile communication terminal user identification and encryption technology advocated by China Unicom and supported by CDMA.
SIM card (subscriber? Identity? Module)? , the subscriber identity card, is the personal data card of GSM digital mobile phone. It is used. A two-level encryption method is developed to store user data, authentication method and key, which can be used to authenticate user identity in GSM system. At the same time, users can connect with the system and exchange information through it.
The mobile phone can only be used with the SIM card. "SIM cards" have different sizes and the same functions, and are suitable for different types of GSM mobile phones. SIM card can be inserted into any mobile phone that meets the GSM standard, and the phone bill is automatically included in the cardholder's bill, no matter what mobile phone it is. ?
The use of SIM card effectively prevents embezzlement, parallel connection and telephone eavesdropping, and ensures the normal communication of users.