ITUT International Numbering Plan

ITU-T Recommendation E.164 specifies that a Country Code (CC), National Destination Code (NDC), and Subscriber Number (SN) be used to route a call to a specific subscriber.

The CC consists of one, two, or three digits. The first digit (1-9) defines world numbering zones. A list of all the defined CCs is found in ITU-T Recommendation E.164 Annex A.

NDC and SN vary in length based on the needs of the country. Neither one has more than 15 digits.

Many other recommendations and specifications for international number plans are found in the E. recommendations from the ITU-T.

Although dial plans might not seem extremely important at the moment, they are crucial to the successful deployment and implementation of Voice over IP (VoIP) or traditional circuit-switched networks.

Regardless of which dialing plan is used in your country, you can expect to see changes in the ways you can dial as well as whom you dial.

0 0

Post a comment