The importance of technology in everyday life has increased tremendously. Many households have multiple cell phones and subscribe to internet services. Businesses require multiple phone lines and fax machines. Other common conveniences, such as pay-at-the-pump gas stations and automatic teller machines (ATMs), each require phone numbers. This growth of the telecommunications industry has led to a phenomenon known as area code “exhaust”. 

What is area code "exhaust"?

An area code reaches exhaust when nearly all of the telephone prefixes (or NXX codes) within that area code are assigned. NXX codes are the first three digits of a phone number that follow the area code. There are 792 possible NXX prefixes in each area code, each consisting of 10,000 numbers. The federal body that administers telephone number initially assigns telephone companies whole NXX codes in blocks of 10,000 numbers.

Who manages area codes?

The Federal Communications Commission (FCC) has jurisdiction over telephone number administration, while the North American Numbering Plan Administration (NANPA) manages the administration and assignment of area codes in the United States. The FCC has given each state the authority to decide how to introduce new area codes. In Ohio, the PUCO makes these decisions.

How are new area codes introduced?

Under PUCO and NANPA guidelines, an area code relief case must be initiated 36 months prior to projected exhaust of an area code. NANPA convenes a planning team to develop all viable options for area code relief. The planning team is required to solicit input from interested members of the telecommunications industry within the affected area code to reach a consensus on an option for area code relief. After a consensus is reached, the following steps occur:

• NANPA will submit a petition to request that the Commission approve the relief alternative chosen by the telecommunications industry. 
• The Commission may hold public hearings in the affected areas or issue an entry to solicit comments and reply comments from the public. 
• The Commission must issue an order adopting an area code exhaust plan after NANPA files a petition. 
  • Any area code exhaust plan adopted by the Commission will include, whenever possible, no less than a six-month permissive dialing period prior to mandatory use of a new area code or dialing pattern.

Which area codes are facing exhaust?

NANPA has notified the PUCO of the following exhaust dates for Ohio area codes:

What are the methods of area code relief?

Geographic split

With a geographic split, the geographic area covered by an existing area code is split into two or more smaller areas. One of the sections retains the existing area code while the other(s) receives a new area code(s), consequently causing customers in that section to have to change the area code associated with their current telephone numbers.

Boundary Realignment

The area code requiring relief is adjacent to an area code which has spare NXX code capacity.  A boundary shift/realignment occurs so that spares codes in the adjacent area code can be used in the area code requiring relief.  As a result, the geographic area of the area code requiring relief shrinks and the geographic area of the area code with spare capacity expands.  Only the customers in the geographic area between the old and new boundaries are directly affected by this change.

All-services overlay

As the name suggests, a new overlay area code “covers” the pre-existing area code, most often serving the identical geographic area. Existing numbers keep the old area code, and only new telephone lines are assigned the new area code. Phone numbers for all types of services are included, whether the phone number is for a phone, cell phone, fax machine or ATM. With an overlay, there are multiple area codes for each geographic area, putting an end to further shrinking of the geographic size of the area code. Subsequent area code relief would likely be another overlay.

Concentrated growth overlay

This overlay may be appropriate where the majority of the new telephone numbers are expected to be concentrated in one section of the existing area code. For example, a fast-growing metropolitan area and a sparsely populated rural area could exist within the same NPA. The overlay area code would be assigned initially to the section of the existing area code experiencing the fastest growth, and new NXXs in that section would be assigned from the new overlay area code. As the NXXs allotted to the rural area near exhaust, the overlay boundaries could expand.

Boundary elimination overlay

With a boundary elimination overlay, the area code requiring relief is adjacent to an area code with spare capacity. The boundary between these two area codes is eliminated, and spare NXX codes from the adjacent NPA are assigned within the original NPA boundary where relief is required. This solution has the advantage of not requiring a new NPA code, but it also shares a limitation of boundary realignment because it offers shorter-term relief.

Technology-specific overlay

This overlay is similar to the all-services overlay, but only certain types of companies, such as wireless and paging companies, would have numbers assigned in the new area code. (This option is newly allowed by the FCC and is not yet in place in Ohio.)

Service-specific overlay

This type of overlay would only affect services, which have numbers that customers do not usually dial. Examples of such services are data lines used for credit card approval, automatic teller machines, unified messaging services, vehicle response systems such as OnStar and “pay-at-the-pump” services. Numbers like these could all be assigned to the service-specific overlay area code and not affect the customers’ dialing patterns in the underlying area code. (This option is newly allowed by the FCC and is not yet in place in Ohio.)

Are there any areas in Ohio that have area code overlays?

Yes. The PUCO established all-services overlays for the 330/234, 419/567, 740/220, 614/380, 937/326 and 513/283 area codes. 

The all-services overlay plan treats all existing 330, 419, 740, 614, 937 and 513 customers equally by allowing them to retain their area code on all existing lines. Only new telephone lines are assigned the new area code. Business customers benefit from an overlay by not having to incur the expense of changing advertising literature, business cards and stationery, and by not having existing and new customers confused about whether they are still in business. Additionally, because there are usually still telephone numbers available in the old area code, there is a high likelihood that new and existing customers can still obtain these numbers under the old area code.

What happens if my area code is designated for an overlay?

If your area is designated for an area code overlay, you will be informed, via bill messages, of a date for "permissive dialing" and a date for "mandatory dialing." During permissive dialing, seven-digit dialing patterns can be used to make local calls. After mandatory dialing has been set, 10-digit dialing must be used to make local calls with the new overlay area code plan. The PUCO recommends that you let family, friends and co-workers know of your new area code or 10-digit dialing as soon as the permissive dialing period begins. During this time, you will also want to see if any reprogramming is needed for fax machines, cell phones, modems, alarm or security systems and other equipment you maintain that uses a telephone number.

Why do customers have to dial ten digits for every phone call in an all-services overlay relief plan?

The FCC has required local 10-digit dialing with area code all-services overlays in order to level the playing field, so that new telephone companies can offer their services without suffering a competitive disadvantage. Without local 10-digit dialing, customers could find it less attractive to choose a new telephone company if doing so would mean always dialing 10 digits, when choosing an established telephone company would allow them to dial only seven digits. In addition, local 10-digit dialing permits a fuller use of all of the numbers within an area code, extending the life of the area code. In order to differentiate between a phone number with the old code and a phone number with the new code, all 10 digits must be dialed.

If 10 or 11 digits are dialed for every call, how do customers know which calls are toll calls and which are local?

The number of digits in a phone call does not determine whether it is a local or a toll call. When in doubt, customers should check with their local service provider or the PUCO. A long-distance call-finder is available in the telephone section of the PUCO website. The telephone section of the website features a long distance call finder that allows consumers to input their home phone number and the number they wish to call to see if will be a local or toll call. It is also helpful to dial 10 digits first. A toll call will not be completed on a 10-digit basis, so if the call goes through with 10 digits, then you will know it is a local call. It is important to remember that an area code change does not affect the cost of a call.

What else is being done to slow the pace of adding new area codes?

Area code changes are inconvenient for both residential and business customers, so it is important to make the numbers in each area code last as long as possible. The PUCO and the FCC are examining several ideas for improving number utilization. These ideas include improving the information about how telephone numbers are being used and requiring telephone companies to prove they need new numbers, as well as other, more technical solutions, such as giving telephone numbers to companies in smaller blocks. As the telephone network technology improves, even more ways to conserve phone numbers, and therefore area codes, are being explored.