The RBOCs of roughly equal size were formed as a result of the 1982 AT&T Consent Decree that AT&T signed with the U.S. Department of Justice, stipulating that it would divest itself of its 22 wholly-owned telephone operating companies. At the time of the consent decree, there were seven RBOCs — Ameritech, Bell Atlantic, BellSouth, NYNEX, Pacific Telesis, Southwestern Bell and U.S. West.
After a series of acquisitions, mergers and name changes (including one in which a combination of several RBOCs reclaimed the original AT&T name), only three of the original seven remain. They are AT&T, Qwest and Verizon. The RBOCs are the Incumbent Local Exchange Carrier (ILECs) in their local markets.
- "The Broadband Availability Gap," OBI Technical Paper No 1, Glossary, at 135 (full-text).