ATIS - Alliance for Telecommunications Industry Solutions
Scope
"The purpose of this document is to consolidate the information contained in earlier industry documents into a single standard document that may be used by the industry as the North American Numbering Plan (NANP) evolves. Further@ this document serves as a ""snapshot"" for anyone interested in numbering issues. This technical document seeks to document the format and values of telephone numbers in the United States portion of the NANP@ thereby coining a ""United States Numbering Plan"" and a ""United States Dialing Plan."" It further defines the other telecommunications industry uses of numbers and describes these uses in the United States. The NANP exists under Country Code 1@ shared among 19 countries@ under the International Telecommunication Union (ITU) Recommendation E.164@ ""The international public telecommunication numbering plan"" (Rec. E.164)."