There are two main reasons why a SIM card may indicate that it is full:
Solution
I. The SIM card's storage space is full.
1, you can copy the text messages existing on the SIM card to the cell phone, and then delete the text messages on the SIM card, so that you can make some memory space for the SIM card.
2. You can copy the phone numbers from your SIM card to your cell phone, and then delete the unimportant phone numbers from your SIM card to free up some memory space on your SIM card.
Two, SIM card chip failure, according to the above situation after processing, still prompted the storage is full, then it is SIM card chip failure, resulting in storage space can not be correctly obtained.
In this case, you can go to the operator to apply for a replacement card, replace the new SIM card to solve the problem.
It should be noted that the storage space of the SIM card is not the memory of the cell phone body or the SD card memory of the phone, generally there will be a capacity of the SIM card on the logo, as shown:
Expansion
The SIM card is a microprocessor chip card, which is equipped with five internal modules, and each module is corresponding to Each module corresponds to a function: microprocessor CPU (8-bit), program memory ROM (3-8kbit), working memory RAM (6-16kbit), data memory EEPROM (128-256kbit) and serial communication unit. These five modules are encapsulated in the SIM card after the copper interface with the ordinary IC card package in the same way. These five modules must be integrated into a single IC, otherwise their security will be jeopardized, as the wires between the chips may become important clues for illegal access and theft of the SIM card.
The power supply of SIM cards is divided into 5V (issued before 1998), 5V and 3V compatible, 3V, 1.8V, etc. Of course, these cards must be used in conjunction with the corresponding cellular phone, i.e., the SIM power supply voltage generated by the cellular phone matches the voltage required by that SIM card.After the SIM card is inserted into the cellular phone, the power port provides power to the modules in the SIM card.
The signal for detecting the presence or absence of the SIM card is generated only when the phone is turned on. When the phone is turned on and the SIM card is not detected, it will prompt "Insert SIM card"; if the SIM card is detected to be present but the communication between the phone and the card can not be realized, it will display "Check SIM card". If the SIM card is detected to be present but the communication between the card and the machine cannot be realized, it will display "Check SIM card"; when the SIM card does not respond to the power-on detection signal, the cell phone will also prompt "Insert SIM card"; when the SIM card is dropped out during power-on use, or due to the poor contact of the loosening or the use of scrap card, the cell phone will prompt "SIM card error "
The storage capacity of SIM card can be 8KB, 16KB, 32KB, 64KB, or even 1MB. Most of them are 16KB and 32KB. How many phone numbers and SMS can be stored in the SIM card depends on the capacity of the data memory EEPROM in the card.