E.164 overview

General syntax

E.164 is the specification for a numeric telephone addressing scheme used by public switched telephone networks (PSTN) and various other data networks. E.164 numbers can address any phone connected to a (PSTN) in the world. PureCloud converts E.164 numbers to other address formats in order for a caller to dial a number and call phones that belong to digital networks.

E.164 numbering follows these standards:

  • An E.164-compliant telephone number can have a maximum of 15 digits.
  • The first one, two, or three digits can represent the country code.
  • The second part is the national destination code, or “NDC.”
  • The last part is the subscriber number, or “SN.”
  • The NDC and SN combined equals the national (significant) number.
  • The combined length of the national (significant) number can’t exceed 15 minus the number of digits in the country code.
  • E.164 is a number-only standard. Number range is 0-9.

PureCloud normalizes an E.164 number by appending tel:+ to the beginning of the number.

North American numbering plan (NANP)

The NANP is a system of numbering plan areas (NPA) in the US, Canada, and the Caribbean.

The traditional formatting convention for NANP phone numbers is (NPA) NXX-XXXX, where:

  • NPA is the area code
  • NXX-XXXX is the subscriber number.
  • The NXX prefix of the subscriber number indicates the local telephone exchange or rate center.