One of the regional telcos that was created as a result of the breakup of American Telephone and Telegraph (AT&T), or one of their successors. AT&T, which was also known as the Bell System (or “Ma Bell”), was divested in 1983 to end its monopoly control and was broken up into several dozen Bell Operating Companies (BOCs), each of which was to supply telephone services to local loop subscribers in a given geographical region. Seven Regional Bell Operating Companies (RBOCs) were also created, each consisting of two or more BOCs. The seven original RBOCs were Ameritech, Bell Atlantic, BellSouth, NYNEX, Pacific Bell, Southwestern Bell, and U S WEST. RBOCs provided local loop services to much of the United States by functioning as local exchange carriers (LECs), while AT&T was left to provide long-distance carrier services and to function as an inter-exchange carrier (IXC). In addition to the RBOCs, dozens of independent LECs serviced different areas.
The telecommunications landscape changed with the passage of the Telecommunications Act of 1996. The act allowed RBOCs and independent LECs to compete with existing IXCs for long-distance carrier business, allowed mergers, and essentially opened up the telecommunications market to all kinds of companies, including cable television companies. Of the seven original RBOCs, only five remain today.