Prior to the great phone rewiring (which was finished by the start of the 1989 school year), all of IU was on the 335 exchange. The rewiring pretty much doubled the number of phones in the dorms (since rooms used to share a phone before that), and they split to the 855/857 exchanges. 856 was added when the new Education building came in, in 1992. AT&T dumped a lot of grant money into the new building, including the new phone switch for the exchange. --Jkonrath 15:14, 6 June 2006 (EDT)
Didn't realize they added the 930 area code overlay to the 812 area code in 2015. Have 930 numbers started showing up in Bloomington?
The original discussion was about dividing 812 into two separate area codes, but there was some debate over a north/south vs east/west split, and they decided on an overlay instead.
See also: http://telecomindiana.com/1812/2014.html