An overlay is the addition of another area code to the same geographic area as an existing area code(s). In the Orlando area of Florida, the 689 area code is being added to the region served by the existing 407 / 321 area code overlay to ensure a continuing supply of telephone numbers. The 407 / 321 overlay region serves Orange, Osceola and Seminole counties, as well as parts of Lake and Volusia counties.
You won't have to change your existing area code or phone number. You'll simply continue to dial or enter the area code and phone number for all calls.