Area Code Overlay
An area code overlay is used when an existing area code is near depletion. This is assigned to the same geographical area, yet current customers don?t have to change their area code. This code is assigned to new customers. The drawback is that 10-digit dialing is required in a area using area code overlay. One example is in the Portland, OR area, where 503 was the original area code, and 971 was added as an overlay. Now even neighbors may have different area codes.