Why do all numbers have to dial the area code + the seven digit number (10 digits) for overlays?
The FCC requires 10-digit dialing for an overlay when two area codes reside in the same geographic area. All calls must be dialed using the area code + the seven-digit telephone number (10 digits) so that customers in the original area code do not have different dialing arrangements. This also prevents older companies (with seven-digit numbers) from having an advantage over a newer company who must use 10-digit numbers.
