E.164

REMORA Category: E

E.164 = CC + NDC + SN is used to describe the structure of a MSISDN (Mobile Station International Subscriber Directory Number), which is the phone number used to identify a mobile subscriber in a global telecommunications network. The MSISDN follows the E.164 international numbering plan, which defines how phone numbers are formatted and standardized for global interoperability.

Let’s break down the components of the formula:

1. E.164 Format:

  • E.164 is an international standard for phone numbers defined by the ITU (International Telecommunication Union). It defines the structure of telephone numbers to ensure they can be used across different countries and networks.
  • An E.164 number can have a maximum of 15 digits, including the country code (CC), and does not include spaces or special characters.

2. CC (Country Code):

  • Country Code (CC) is the international dialing code that identifies the country of the mobile subscriber. It is typically 1 to 3 digits long. For example:
    • USA: 1
    • UK: 44
    • India: 91
    • Italy: 39
  • The country code is essential when dialing internationally, ensuring the call is routed to the correct country.

3. NDC (National Destination Code):

  • The National Destination Code (NDC), also known as the Network Destination Code, identifies a specific network or region within a country. In some cases, this could be the Mobile Network Code (MNC) or an area code in fixed-line numbering. It helps route the call to the correct mobile network operator within the country.
  • The length of the NDC varies depending on the country and operator.

4. SN (Subscriber Number):

  • The Subscriber Number (SN) is the unique number assigned to each individual subscriber within a specific network. It identifies the individual mobile user within the network defined by the NDC.
  • This part of the MSISDN is specific to the subscriber, ensuring each phone number is unique within the operator’s network.

Example of an E.164 MSISDN: Consider the number +44 7700 123456:

  • CC (Country Code): 44 (UK)
  • NDC (National Destination Code): 7700 (a specific mobile operator or network in the UK)
  • SN (Subscriber Number): 123456 (the unique number assigned to the subscriber)

Please take a look also at E.212 and E.214 pages.

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