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Indiana: History | Northern (219, 260, 269) Central (317, 463, 765) Southern (812, 930)
Indiana - Area Code History
In 1947 the Bell Telephone System (AT&T) assigned 86 area codes across the entire United States. Two area codes were assigned to Indiana. Area code 317 served Indianapolis north to Michigan. Area code 812 served Bloomington south to Kentucky.
The first map to the left reflects the 1947 area code assignment and Bell System served exchanges in Indiana. The remainder of Indiana was served by General Telephone, United Telephone and other independent and cooperative phone companies. The map reflects the attitude of Bell Telephone that "we are the phone company". Interconnection between Bell System and other companies was a sore point.
(Note: Adjustments along the 317/812 border are not documented or shown here. Company footprints estimated based on modern exchange coverage and ownership.)
In 1948 Bell assigned the first new area code ... the first "split" of any area code in the country. Area code 317 was divided into 219 on the north retaining 317 for Indianapolis and central Indiana. (The northern area code primarily served by United Telephone and General Telephone companies.)
Did the Area Code Matter?
While area codes were first assigned in 1947, they were not in general use by the public. Direct dialing of long distance numbers did not begin until 1951. Some rural exchanges did not have direct distance dialing until the 1990s. General Telephone had their own issues with Bell's "area code numbers" and continued to use city names for their operators to route long distance calls in the 1960's and 1970's. A caller in GTE's Lafayette who asked for a 312 area code number would be asked for the city (Chicago).
The use of direct distance dialing grew as each exchange was updated to be able to automatically route and track each call. The tracking was an important consideration, as without tracking there would be no billing. Until systems were updated, the common way of placing a long distance call was to speak to the operator, who would dial the area code and number for the customer.
Indiana's 1948 area codes survived until 1997 when 317 was split (a "donut" keeping Indianapolis in 317 and placing everything around it in 765). The original 219 was split into three codes in 2002. The original 812 was overlaid in 2015 and 317 was overlaid in 2016.
The 1990s and early 2000s were boom years for area codes. New area codes were being introduced across the nation with short expected lifetimes. As number conservation (number pooling and portability) took effect the boom ended. The short life of area codes - expecting additional splits or ovelays within less than a decade - led to decisions that can now be regretted. Fortunately for the 317 and 219 relief the IURC did not make those errors. They approved rational splits that will serve Indiana for decades.
The last approved split in the US took affect in 2007 in New Mexico (575 split from 505). When the question of relief for 812 and 317 came before the IURC they followed the industry. Not wanting to decide who kept 812 and who changed to 930, the IURC decided to overlay 930 over 812 (forcing 10 digit dialing on all users in 812). Overlaying 463 on 317 was a more natural fit as there was no good dividing line for 317.