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. Genesys Cloud 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.

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

Note: Numbers entered into the Other phone field on a user profile do not need to be entered in E.164 format. This field is often used for assigning DIDs to users which are intended to be reached on an external platform. The Other phone field is not considered an internal number to Genesys Cloud and may be manipulated by the dial plan on external phone trunks.

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.