The MIN is a number that uniquely identifies a mobile phone working under TIA standards for cellular and PCS technologies (e.g. EIA/TIA–553 analog, IS–136 TDMA, IS–95 or IS-2000 CDMA).
MIN usage became prevalent for mobile number portability to switch providers.
It can also be called the MSID (Mobile Station ID) or IMSI_S (Short IMSI).
The rules for deriving the MIN from the 10-digit telephone number are given in the IS-95 standard.
In most second generation systems, temporary numbers are assigned to the handset when routing calls as a security precaution.