North American Numbering Plan - Wikipedia
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The map of North American area codes, as it was... - Maps on the Web
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The original 1947 Telephone Area Code Map - Codes were assigned based on population and time it took to dial the code on a rotary phone dial. High population areas got small
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File:The Bell System technical journal (1922) (14570186909).jpg - Wikimedia Commons
1 The Commission notes that, although the North American Numbering Plan Administrator (NANPA) has reserved this number for use i
