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Indiana Utility Regulatory Commission

IURC > Communications Services Division > 930 Area Code Implementation > Area Code Relief FAQs Area Code Relief FAQs

What makes up a telephone number?

Our telephone numbering system operates under the North American Numbering Plan, which was developed in 1947 by AT&T and subsequently adopted by the Federal Communications Commission (FCC). It established the 10-digit scheme we use today.

  • The "NPA" (Number Plan Area) is the area code. Indiana currently has six area codes: 219, 574, 260, 765, 317, and 812.
  • The "NXX" is the central office (CO) code, and is also referred to as the "prefix." An NXX serves a specific exchange or rate center.
  • The XXXX is the line number for the customer.

How many telephone numbers are in each area code?

Each area code contains 792 usable telephone prefixes, which are the 3-digit numbers that follow the area code. Each prefix has 10,000 telephone numbers, and each area code has 7.92 million telephone numbers. 

Why aren't more numbers available?

Population growth, economic progress and the demand for new services (e.g., cell phones, faxes, and computers) have led to a number shortage.

What are the exhaust dates for Indiana's area codes?

How are telephone numbers assigned? 

Telephone prefixes are assigned to carriers in particular geographic areas (rate centers). In the past, numbers used to be assigned in blocks of 10,000, which had to the potential to result in stranded telephone numbers that were left unused. In order to address this problem, the IURC petitioned the FCC for authority to implement 1,000 block number pooling for more granular assignment. Upon receiving approval, pooling became mandatory in order to extend the life of the 812 area code.

What is the area code relief process?

As the 812 area code was approaching its projected exhaust date, the NANPA called industry stakeholders together to discuss and recommend a form of relief. The industry then filed a petition for relief with the IURC on August 3, 2012 in Cause No. 44233. The IURC set a procedural schedule, holding educationsal sessions, field heraings, and evidentiary hearings to determine the appropriate relief method. On July 31, 2013, the IURC issued its Order approving the overlay of a new area code, 930.

What are the options for area code relief?

The most common methods of relief for area codes nearing exhaust include a geographic split or an overlay. A geographic split divides the existing area code into two or more areas with one of the areas retaining the existing area code and the other area(s) being assigned a new area code. An overlay, on the other hand, allows a new area code to be assigned over the same geographic area as the existing area code, which would allow current users to keep their numbers; however, it also means a neighbor or new business could have a different area code although they may be located next door. This would result in the need for 10-digit dialing (the area code and the seven-digit telephone number) for all calls, regardless of whether they are local or long distance.

How quickly will the change go into effect?

The transition is introduced in two steps to familiarize consumers with the changes and allow time for adjustments. These steps are detailed below:

  1. Permissive dialing - Permissive dialing allows callers to connect with the telephone number they are trying to reach using the old method. During this transitional period, customers should make an effort to begin using the new method. Generally, this period of time lasts six months.
  2. Mandatory dialing - When the transitional period ends, callers are notified if they are still using the old method. Incorrectly dialed calls receive a recorded announcement informing them of the new procedure. In order to proceed with the call, they must use the appropriate area code. After the recording period ends, callers who do not use the correct area code may reach a wrong number.

What's the best way to adjust to the transition?

It is recommended that anyone affected by the change reprogram their mobile devices and/or update their address books.

Will my phone bill increase?

No. The new area code(s) will not change rates, local calling areas, or seven-digit phone numbers.

Will calls between a telephone number with the 812 area code and a telephone number with the 930 area code be considered long distance?

No. They will not be considered long distance. Calls that were local before the introduction of the new area code will remain local calls. Local calling areas do not change when a new area code is established.