When there's a risk of an area code running out of phone numbers, an 'Overlay Area Code' is created that has the same geographic boundaries as the existing area code. In this case, the 709 code has been Overlayed with the 879 area code. New phone numbers in the Esker area will be assigned with one of these codes: 709 or 879. As a result, placing a call in the Esker area will require 10-digit dialing (where you enter both the area code and then the phone number).