Glossary:International Mobile Subscriber Identity (IMSI)

The International Mobile Subscriber Identity, abbreviated as IMSI, is the internationally standardised unique number to identify a mobile subscriber, as defined in ITU-T Recommendation E.212.

The IMSI consists of:

When dealing with devices in a single country, the MCC can be dropped out and the combination of the MNC and the MSIN, which is a 9-digit code identifying the subscriber, is usually referred to as the National Mobile Subscriber Identity (NMSI).

As long as a subscriber has not changed his SIM card, the IMSI will remain the same even when switching mobile device.

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