Linked Numbering Scheme - North America

North America

The terminology "linked numbering scheme" is not used in the North American Numbering Plan as all numbers are constructed with +1, then a fixed-length area code (three digits) which covers not one exchange but all or a large part of a state or province. This is followed by seven more digits, of which the first three identify an individual local exchange.

It is presumed that each area will, by default, contain many different exchanges in different towns (or different parts of a large city). A local call in this scheme, standardised for the 1951 introduction of direct-dial long distance calling, was originally dialled as a fixed-length seven-digit number. A "local call" does not infer "same area code" (or vice-versa) and the local (usually flat-rate) calling area of all but the most isolated villages would contain multiple exchanges and one or more adjacent towns.