How many short messages can be stored on the SIM card?

Capacity depends on the SIM card, not the number field. SIM cards are divided into 8K, 16K and 32K. (written on the back of the SIM card). Now it is generally 16K, 32K. The higher the value, the more messages there are in the SIM phone book.

When the information on the SIM card reaches the upper limit, it will be automatically saved to the mobile phone, while only 40 pieces of information are saved in the SIM card.

In addition, when sending a short message, the digital capacity of the short message is 70 characters (a rigid regulation of mobile operators). No matter what the beginning of the card is, it is the same, and this cannot be changed.

Extended data

Common faults of SIM card

1. When the PIN function of the SIM card is started, the GSM system and the mobile phone will automatically verify the validity of the SIM card after each start. At this time, if the wrong PIN code is entered three times in a row, the card will be locked. Don't continue the operation at this time, or the operation card will burn after ten times, causing unnecessary losses.

The solution is to find the network operator to unlock it. When the SIM card is accidentally lost, you should immediately apply to the network operator for loss reporting to avoid the SIM card being stolen. After reporting the loss of the SIM card, you can immediately apply to the network operator for a replacement.

2. When there is no response when the mobile phone is inserted into the SIM card, or when the SIM card is inserted, a bad error is displayed, the SIM card will be turned off or the contact will be poor, or this problem will occur when using a waste card. If the fault of replacing a new card still exists, the fault usually appears in the power supply part of the SIM card.

At the power end, clock end and data end of the SIM card socket, the card reading signal can be observed through the oscilloscope at the moment of starting. If there is no signal, the peripheral resistance and capacitance elements of the power switch of the SIM card should be welded with the card.

3.SIM card can be used on one mobile phone, but not on another. Perhaps the functions of "network restriction" and "user restriction" are set in the mobile phone.

The restriction function of mobile phone can be started by 16-bit network control code (NCK) and user control code (SPCK). This kind of fault needs to be solved by network operators, and sometimes it is caused by insufficient power supply or poor contact of SIM card.