What is E.164?
E.164 is an ITU-T recommendation for international PSTN numbering. It is meant to be a way to globalize phone numbers, which means to define and standardize the format of phone numbers around the world. Historically, E.164 evolved from the ITU-T E.163 created in 1997.
E.164 introduces a powerful symbol: the plus sign “+”. If you take a look at the résumé of an international consultant or a Sales Manager who travels frequently, did you notice something special in the phone number section? The plus sign for example, in front of the phone number? That’s what I’m talking about. The phone number of our Sales Manager is written in the E.164 format.
For example, in the US, if you want to dial long distance number 512.555.1234, its E.164 format will be +1.512.555.1234. You won’t dial the dots of course they’re just seperators for easy reading
An international number in the E.164 format has the following parts:
- Exit code: the code to exit the current country
- Country code: the code related to the country of the called party
- Subscriber code: identifies the called party in his country
Cisco Call Manager E.164 support
Cisco CUCM supports E.164 in its constructs. Indeed, you can create Translation Patterns, Hunt Pilots, Translation Patterns and Transformation Patterns with the plus sign in them.