What is the difference between the “overlay” and a “geographic split” method of adding a new area code?
Geographic split: The geographic area covered by an existing area code is split in two. One section retains the existing area code, while the other receives a new area code. The benefit of a geographic split is that an area code remains defined as a geographic area – customers know something about the location of the people they are calling. Within each area local dialing remains the same as it is now. The down-side of a geographic split is that many customers must cope with the inconvenience of changing their area code and some customers along the area code boundary may have to dial the area code to place local calls. Overlay: As the name suggests, the new area code “overlays” the pre-existing area code, most often serving the identical geographic area. The benefit of an overlay is that customers retain their existing area codes. Only new lines get the new area code. An overlay requires all customers, including those with telephone numbers in the pre-existing area code, to dial area c