Their headquarters are at 225 West Randolph St., Chicago, IL. After the 1984 Bell System Divestiture, Illinois Bell became a part of Ameritech, one of the 7 original Regional Bell Operating Companies. The Illinois Bell name continued to be used until January 1993, when Ameritech dropped all of their individual Bell Operating Company names in favor of using their corporate name, Ameritech, for marketing purposes. Illinois Bell started doing business as Ameritech Illinois.
In 1998, Ameritech announced intentions to merge with SBC, another former RBOC. Though the merger wasn't well received at first, it was allowed to occur with some conditions. The two companies were officially merged as of October 8, 1999. The Ameritech name continued to be used until 2002, despite the merger.
In 2001, the company started doing business as SBC Ameritech Illinois.
In 2002, SBC dropped the Ameritech name in favor of "SBC" as a national brand. On January 1, 2003, Illinois Bell, for regulatory business, was renamed Illinois Bell Telephone Company d/b/a SBC Illinois. Illinois Bell's trade name was changed once again in 2006, following conclusion of SBC Communications' purchase of AT&T, to Illinois Bell Telephone Company d/b/a AT&T Illinois.
A Regional Bell Operating Company (RBOC) was a corporate entity created as result of the antitrust lawsuit by the U.S. Department of Justice against the American Telephone and Telegraph Company (AT&T) in 1974 and settled in the Modification of Final Judgment on January 8, 1982.
AT&T Teleholdings, Inc., formerly known as Ameritech Corporation, is an American telecommunications company that arose out of the 1984 AT&T divestiture. Ameritech was one of the seven Regional Bell Operating Companies that was created following the breakup of the Bell System. Ameritech was acquired in 1999 by SBC Communications, which subsequently acquired AT&T Corporation in 2006, becoming the present-day AT&T.
BellSouth, LLC was an American telecommunications holding company based in Atlanta, Georgia. BellSouth was one of the seven original Regional Bell Operating Companies after the U.S. Department of Justice forced the American Telephone & Telegraph Company to divest itself of its regional telephone companies on January 1, 1984.
Pacific Telesis Group was one of the seven Regional Bell Operating Companies, sometimes also referred to as "RBOCs" or "Baby Bells", created in 1983 in preparation of the breakup of AT&T as a holding company for Pacific Bell and Nevada Bell, Pacific Telesis International and several other non-regulated companies including PacTel Mobile Services and PacTel InfoSystems. It was acquired by SBC Communications in 1997.
Houston Cellular was a Houston-based cell phone company which provided AMPS and D-AMPS (TDMA) service in the Greater Houston area. It was formed in 1983 and was operated as a partnership between LIN Broadcasting Corp., Mobile Communication Corp. of America and BellSouth Co. Its headquarters were located in Houston, Texas.
Cellular One is the trademarked brand name that licenses services used by several cellular service providers in the United States. The brand was sold to Trilogy Partners by AT&T in 2008 shortly after AT&T had completed its acquisition of Dobson Communications. Cellular One was originally the trade name of one of the first mobile telephone service providers.
The breakup of the Bell System was mandated on January 8, 1982, by a consent decree providing that AT&T Corporation would, as had been initially proposed by AT&T, relinquish control of the Bell Operating Companies, which had provided local telephone service in the United States. This effectively took the monopoly that was the Bell System and split it into entirely separate companies that would continue to provide telephone service. AT&T would continue to be a provider of long-distance service, while the now-independent Regional Bell Operating Companies (RBOCs), nicknamed the "Baby Bells", would provide local service, and would no longer be directly supplied with equipment from AT&T subsidiary Western Electric.
Ameritech Mobile Communications, LLC was the first company in the United States to provide cellular mobile phone service to the general public. Cell service became publicly available in Chicago on October 13, 1983. The company was a division of Ameritech which, as of January 1, 1984, was the holding company of Illinois Bell, Michigan Bell, Wisconsin Bell, Ohio Bell, and Indiana Bell, which provides landline service to the Great Lakes region. From around 1986, Cincinnati Bell held a 45% stake in the company. Originally named Ameritech Mobile Communications, it later became known as Ameritech Cellular.
Michigan Bell is the subsidiary of AT&T serving the state of Michigan. Following the Bell System divestiture on January 8, 1984, the company became a subsidiary of Ameritech, the Regional Bell operating company that served the midwestern United States. Ameritech was subsequently acquired by SBC Communications, which later changed its name to AT&T.
The Ohio Bell Telephone Company, now doing business as AT&T Ohio, is the Bell Operating Company serving most of Ohio and parts of West Virginia. It is a wholly owned subsidiary of AT&T.
Indiana Bell Telephone Company, Incorporated, is the Bell Operating Company serving Indiana. It is an indirect subsidiary of AT&T Inc., owned by AT&T Teleholdings.
Wisconsin Bell, Inc. is the name of the Bell Operating Company serving Wisconsin. It is owned by AT&T through AT&T Teleholdings, originally known as Ameritech.
SBC Long Distance LLC is a long-distance telephone company owned by AT&T that does business as AT&T Long Distance. SBC Long Distance competes with other long-distance providers who provide service within some of the Bell Operating Company service boundaries of AT&T. SBC Long Distance is a separate subsidiary than AT&T Communications, the incumbent long-distance carrier for most of the country acquired in the SBC merger with AT&T.
Dex One Corporation was an American marketing company providing online, mobile and print search marketing via their DexKnows.com website, print yellow pages directories and pay-per-click ad networks in the U.S.
SBC Telecom, Inc. d/b/a AT&T Small Business is a CLEC owned by AT&T that offers local telephone service outside the AT&T Bell Operating Company regions. It was formed in 1999 following provisions that required SBC Communications to offer telephone service outside its boundaries in order to get approval to merge with Ameritech.
The Bell System was a system of telecommunication companies, led by the Bell Telephone Company and later by the American Telephone and Telegraph Company (AT&T), that dominated the telephone services industry in North America for over 100 years from its creation in 1877 until its antitrust breakup in 1983. The system of companies was often colloquially called Ma Bell, as it held a vertical monopoly over telecommunication products and services in most areas of the United States and Canada. At the time of the breakup of the Bell System in the early 1980s, it had assets of $150 billion and employed over one million people.
Southwestern Bell Telephone Company is a wholly owned subsidiary of AT&T. It does business as other d.b.a. names in its operating region, which includes Arkansas, Kansas, Missouri, Oklahoma, Texas, and portions of Illinois. The company is currently headquartered in Dallas, Texas at One AT&T Plaza.
The history of AT&T dates back to the invention of the telephone. The Bell Telephone Company was established in 1877 by Alexander Graham Bell, who obtained the first US patent for the telephone, and his father-in-law, Gardiner Greene Hubbard. Bell and Hubbard also established American Telephone and Telegraph Company in 1885, which acquired the Bell Telephone Company and became the primary telephone company in the United States. This company maintained an effective monopoly on local telephone service in the United States until anti-trust regulators agreed to allow AT&T to retain Western Electric and enter general trades computer manufacture and sales in return for its offer to split the Bell System by divesting itself of ownership of the Bell Operating Companies in 1982.
The Southern New England Telephone Company, doing business as Frontier Communications of Connecticut, is a local exchange carrier owned by Frontier Communications.
AT&T Communications, Inc., doing business as AT&T Communications, was a division of the AT&T Corporation that, through 23 subsidiaries, provided interexchange carrier and long-distance telephone services.
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