Straining the number supply is the exponential increase of pagers, fax machines, modems and cellular phones, as well as burgeoning competition in telecommunications services. But 54 others will soon be depleted. Each new area code generates about 7.9 million numbers. In Michigan, the regions now covered by the 517 and 810 area codes will get still additional codes. But many more dialing codes are needed.
Overlays are far less expensive and disruptive for both customers and service providers.
Existing numbers remain unchanged, but local calling may require 10-digit dialing. Oakland County officials, for example, insist upon an exclusive area code for their county. State regulators are understandably anxious about crossing the state's most prosperous county. But in bowing to Oakland's demands, thousands of numbers go unused and remain unavailable to other communities. Designating area codes by geographic boundaries is an obsolete formula.