Mobile Station ISDN
Formal
Mobile Station ISDN (MSISDN) is a number uniquely identifying a subscription in a GSM or a UMTS mobile network. The MSISDN, together with IMSI are two important numbers used for identifying a mobile subscriber.
Practical
The MSISDN together with IMSI are two important numbers used for identifying a mobile subscriber. The latter is stored in the SIM, i.e. the card inserted into the mobile phone, and each IMSI uniquely identifies the mobile station, its home wireless network, and the home country of the home wireless network, while the former is the number used for routing calls to the subscriber.
