Editing Ten-digit dialing (section)

==History==
The implementation and expansion of the North American Numbering Plan between 1947 and 1992 preserved a long-standing practice in the United States and Canada that callers should only need to dial the local seven-digit telephone number when placing a call within the caller's exchange area or within the home numbering plan area (NPA). In [[seven-digit dialing]], callers dial the three-digit central office code and the four-digit station number of the destination telephone if it resides in the same numbering plan area. Dialing of an area code before the telephone number, referred to as ten-digit dialing, was only necessary for ''foreign NPA'' (FNPA) calls.

Some communities with significant parts on both sides of an area code boundary implemented [[central office code protection]], where possible, to ensure the same seven-digit local number was not assigned in two different area codes in the same city to assure seven-digit dialing in the entire community.