What is MSISDN Mobile Station ISDN number

Technical details of the MSISDN (Mobile Station International Subscriber Directory Number):

1. Definition and Purpose:
   • The MSISDN is a unique identification number assigned to a mobile cellular service subscriber. It serves as the “phone number” associated with a mobile device.
   • In telecommunication, the MSISDN is used to identify and route calls and messages to mobile phones.
2. Components of MSISDN:
   • The MSISDN comprises several elements that provide specific information:
     • Country Code (CC): A 1-3 digit code identifying the country or geographical area.
     • National Destination Code (NDC): Part of the number plan specific to each country, identifying one or part of a Public Land Mobile Network (PLMN).
     • Subscriber Number (SN): The unique number assigned to the subscriber within the PLMN.
   • The complete MSISDN is formed by concatenating these components.
3. Format and Length:
   • The ITU-T recommendation E.164 defines the maximum length of an MSISDN as 15 digits.
   • The format varies slightly based on the mobile network technology:
     • GSM and DCS 1800 (PCS 1900):
       • MSISDN = 88 + 017 + SN
       • Example: +880 15 00121121 (Teletalk Hotline Number)
     • GSM variant DCS 1800:
       • MSISDN = 88 + 017 + SN
       • Example: +880 15 00121121
   • The minimum length of the MSISDN is specified by national numbering plans in each country.
4. Role in Mobile Networks:
   • The MSISDN is used for:
     • Routing calls to the subscriber.
     • Connecting incoming calls to the mobile phone.
     • Identifying the subscriber’s home wireless network and home country.
     • Differentiating between subscribers within the same network.
5. Comparison with IMSI:
   • The IMSI (International Mobile Subscriber Identity) is another crucial number used for identifying a mobile subscriber.
   • While the IMSI is stored in the SIM card, the MSISDN is dialed to connect calls to the mobile phone.
   • Unlike the IMSI, the MSISDN can change over time, associating different numbers with the same SIM.