A predetermined numeric sender identification (the mobile number that is displayed on the recipient’s cell phone) that cannot be modified according to user needs and follows the standard MSISDN format – The ITU Telecommunication Standardization Sector recommendations limits the maximum length of an MSISDN to 15 digits. 1-3 digits are reserved for country code with prefixes not included.
The minimum length of the MSISDN is not specified by ITU Telecommunication Standardization Sector but is instead specified in the national numbering plans by the telecommunications regulator in each country.