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. Genesys Cloud converts E.164 numbers to other address formats so that a caller can dial a number and call phones that belong to digital networks.

Numbers in the E.164 format contain a Plus sign (+), the Country code, the Area code/national destination code, and the Local phone number.

For example, in the USA, the country code is 1. So the E.164 format of the number 317-555-1212 would be +13175551212. In the UK, the country code is 44. So the E.164 format of the number 20-7183-8750 would be +442071838750