Editing SIM card (section)

=== International mobile subscriber identity (IMSI) ===
SIM cards are identified on their individual operator networks by a unique ''[[international mobile subscriber identity]]'' (IMSI). [[Mobile network operator]]s connect mobile phone calls and communicate with their market SIM cards using their IMSIs. The format is:
* The first three digits represent the [[Mobile country code]] (MCC).
* The next two or three digits represent the [[Mobile network code]] (MNC). Three-digit MNC codes are allowed by E.212 but are mainly used in the United States and Canada. One MCC can have both 2 digit and 3 digit MNCs, an example is 350 007.
* The next digits represent the [[Mobile identification number]] (MSIN).
* Normally there are 10 digits, but can be fewer in the case of a 3-digit MNC or if national regulations indicate that the total length of the IMSI should be less than 15 digits.
* Digits are different from country to country.
{{Anchor|Authentication key}}