The third category is related business codes, such as personal identification code (PIN), unlock code (PUK), billing rate, etc. The fourth category is the telephone directory. Almost all user information is stored in the SIM card, so the SIM card is also called "user information identification card". SIM card can be divided into big card and small card. The small card is called "plug-in SIM card", which is the chip on the big card.

The second category is temporarily stored data related to the network. Such as location area identification code (LAI), mobile user temporary identification code (TMSI), public telephone network code prohibited from access, etc.