what is the maximum length of phone number
Telephone numbering plan The International Telecommunication Union (ITU) has established a comprehensive numbering plan, designated E.164, for uniform interoperability of the networks of its member state or regional administrations. It is an open numbering plan, however, imposing a maximum length of 15 digits to telephone numbers. The standard defines a country calling code (country code) for each state or region which is prefixed to each national numbering plan telephone number for international destination routing.
Long-distance calling "On October 9, 1876, Alexander Graham Bell and Thomas A. Watson talked by telephone to each other over a two-mile (3 km) wire stretched between Cambridge and Boston. It was the first wire conversation ever held. Yesterday afternoon the same two men talked by telephone to each other over a 3,400-mile (5,500 km) wire between New York and San Francisco. Dr. Bell, the veteran inventor of the telephone, was in New York, and Mr. Watson, his former associate, was on the other side of the continent. They heard each other much more distinctly than they did in their first talk thirty-eight years ago."