Pre-1956 international holdings Before the 1956 break-up, the Bell System included the companies listed below, plus those listed in the pre-1984 section. Northern Electric and the Caribbean regional operating companies were considered part of the Bell System proper before the break-up. Nippon Electric was considered a more distant affiliate of Western Electric, and through its own research and development adapted the designs of Western Electric's North American telecommunications equipment for use in Japan, which to this day gives much of Japan's telephone equipment and network a closer resemblance to North American
ANSI and
iconectiv standards than to European-originated
ITU-T standards. Before the 1956 break-up, Northern Electric was focused on manufacturing, without significant telecommunication-equipment research & development of its own. The operation of Japan's NTT during the
post-World War II occupation was considered an administrative adjunct to the North American Bell System. •
Nortel Networks Corporation, formerly Northern Telecom, an equipment-manufacturing company • Northern Electric, a former telecommunications equipment-manufacturing subsidiary of Western Electric • Dominion Electric, a former recording equipment-manufacturing company • Various former
Caribbean regional operating companies, sold to
ITT •
NEC, an equipment-manufacturing company in Japan • Nippon Electric, a former telecommunications equipment-manufacturing company 54% owned by Western Electric •
NTT, a telecommunications company in Japan that was administered by AT&T as part of General Douglas MacArthur's post-WWII reconstruction
Pre-1984 breakup Immediately before the 1984 break-up, the Bell System had the following
corporate structure:
American Telephone and Telegraph Company, the parent
holding company and
long-distance carrier Local operating companies: •
Bell of Pennsylvania •
C&P Telephone •
C&P Telephone of Maryland •
C&P Telephone of West Virginia •
C&P Telephone of Virginia •
Diamond State Telephone Company •
Illinois Bell •
Indiana Bell •
Michigan Bell •
Mountain Bell •
Malheur Bell •
New England Telephone •
New Jersey Bell •
New York Telephone •
Nevada Bell •
Northwestern Bell •
Ohio Bell •
Pacific Telephone •
Pacific Northwest Bell •
South Central Bell •
Southern Bell •
Southwestern Bell •
Wisconsin Bell Partly owned local operating companies: •
Cincinnati Bell (22.7% owned) •
Southern New England Telephone (16.8% owned)
Other subsidiaries: •
Western Electric Co., Inc. (equipment manufacturing) •
Bell Telephone Laboratories, Inc. (
research and development, co-owned between AT&T and Western Electric) •
Bellcomm, Inc. (1963–1972; formed to support the
Apollo program)
1984 On January 1, 1984, the former components of the Bell System were structured into the following
Regional Bell Operating Companies (RBOCs), which became known as Baby Bells. •
American Information Technologies Corporation, branded as Ameritech •
Illinois Bell Telephone Company •
Indiana Bell Telephone Company, Incorporated •
Michigan Bell Telephone Company • The
Ohio Bell Telephone Company •
Wisconsin Bell, Inc. •
American Telephone and Telegraph Company •
AT&T Communications, Inc. •
AT&T Information Systems, Inc. •
AT&T Technologies, Inc. •
Bell Telephone Laboratories, Inc. •
Bell Atlantic Corporation •
New Jersey Bell Telephone Company •
The Bell Telephone Company of Pennsylvania •
The Chesapeake and Potomac Telephone Company •
The Chesapeake and Potomac Telephone Company of Maryland •
The Chesapeake and Potomac Telephone Company of West Virginia •
The Chesapeake and Potomac Telephone Company of Virginia •
The Diamond State Telephone Company •
Bell Communications Research, Inc., owned equally by all of the
Baby Bells •
BellSouth Corporation •
Southern Bell Telephone and Telegraph Company •
South Central Bell Telephone Company •
Cincinnati Bell, Inc. • Cincinnati Bell Telephone Company •
NYNEX Corporation •
New York Telephone Company •
New England Telephone and Telegraph Company •
Pacific Telesis Group •
Pacific Bell Telephone Company •
Nevada Bell Telephone Company •
Southwestern Bell Corporation •
Southwestern Bell Telephone Company •
The Southern New England Telephone Company •
U S WEST, Inc. •
Northwestern Bell Telephone Company •
Pacific Northwest Bell Telephone Company • The
Mountain States Telephone and Telegraph Company •
Malheur Home Telephone Company
Today After 1984, multiple mergers occurred of the operating companies and between them, so that some components of the former Bell System are now owned by companies independent of the historic Bell System, including foreign telecommunications firms. The structure of the companies today is as follows.
Remaining "Regional Bell Operating Companies" •
AT&T Inc., a holding company •
AT&T Corp., a current subsidiary •
AT&T Teleholdings, Inc. (formerly Ameritech Corporation), a current subsidiary, also includes now defunct
Pacific Telesis •
Illinois Bell Telephone Company, a regional LEC •
Indiana Bell Telephone Company, Incorporated, a currently existing regional LEC •
Michigan Bell Telephone Company, a regional LEC •
Pacific Bell Telephone Company, a regional LEC •
Nevada Bell Telephone Company, a regional LEC, omitted from the
MFJ • The
Ohio Bell Telephone Company, a regional LEC •
Wisconsin Bell, Inc., a regional LEC •
BellSouth LLC, a current subsidiary. Its two operating companies merged into one: •
BellSouth Telecommunications, LLC, a regional LEC, includes Southern Bell & South Central Bell •
Southwestern Bell Telephone Company, a regional LEC •
Verizon Communications, Inc., formerly
Bell Atlantic Corporation, a holding company •
NYNEX LLC, a former RBOC holding company •
Verizon New England, Inc., a regional LEC •
Verizon New York, Inc., a regional LEC • Verizon Delaware LLC, a regional LEC •
Verizon Maryland, Inc., a regional LEC •
Verizon New Jersey, Inc., a regional LEC •
Verizon Pennsylvania, Inc., a regional LEC •
Verizon Washington, D.C., Inc., a regional LEC •
Verizon Virginia, Inc., a regional LEC •
Frontier Communications Corporation, formerly an independent LEC holding company, acquired by Verizon in 2026 •
Frontier Communications ILEC Holdings, Inc., an LEC holding company created by
Verizon and sold to Frontier in 2010 •
Frontier West Virginia, Inc., a regional LEC, formerly C&P Telephone of West Virginia •
The Southern New England Telephone Company, a regional LEC that AT&T owned 16.8% of before 1984 and thus was left separate by the 1984 break-up (subsequently acquired by SBC and then sold to Frontier by the new AT&T after the SBC-AT&T merger) •
Lumen Technologies, Inc. (formerly
CenturyLink, Inc.), an independent LEC holding company •
Qwest Communications International, Inc., a holding company acquired in 2011; originally a non-Bell company, acquired and merged
U S WEST in 2000. • Qwest Services Corporation, a holding company within the Qwest corporate structure •
Qwest Corporation, a regional LEC, originally Mountain Bell, includes defunct Malheur Bell, Northwestern Bell, Pacific Northwest Bell ;Other "Bell Operating Companies" The following telephone companies are considered independent of the
Baby Bells: •
Cincinnati Bell, Inc., an independent LEC holding company, owned by
Macquarie Infrastructure and Real Assets in 2021 and doing business as
Altafiber. • Cincinnati Bell Telephone Company LLC, a LEC of which AT&T owned 27.8% before 1984 and thus was left separate in the 1984 break-up •
Consolidated Communications Holdings, Inc., an independent LEC holding company •
FairPoint Communications, Inc., an LEC holding company sold to Consolidated in 2017 •
Consolidated Communications of Northern New England Company LLC, a regional LEC created when
Verizon New England lines in
Maine and
New Hampshire were sold to
FairPoint in 2008 •
Consolidated Communications of Vermont Company LLC, a regional LEC created when Verizon New England lines in
Vermont were sold to FairPoint in 2008 ; Other "Bell System" companies The following companies were divested after 1984 from
AT&T Corp. or the
Baby Bells and do not provide telephone service. •
Lucent Technologies, a research and equipment manufacturing company spun-off in 1995; merged with French company Alcatel in 2006 to form
Alcatel-Lucent which was acquired by Finland's
Nokia Corporation in 2016 •
Western Electric Company, Incorporated, a former telecommunications and recording equipment-manufacturing company that ceased to have that name as of the 1984 break-up • Alcatel-Lucent Bell, a subsidiary of Alcatel-Lucent that was founded in
Antwerp,
Belgium in 1882, by Western Electric; came into Alcatel-Lucent ownership via
ITT and Alcatel •
Bell Telephone Laboratories, Inc., the former AT&T-corporate research unit known as Bell Labs: also spun-off to Lucent Technologies, became
Nokia Bell Labs in 2016 •
Avaya, Inc., an equipment manufacturing company spun-off from Lucent in 2000 •
LSI Corporation, a holding company •
Agere Systems, incorporated in 2000, the former Micro Electronics subsidiary of Lucent; was then spun-off in 2002 and acquired by
LSI in 2007 •
Systimax Solutions, the
Western Electric Structured Cabling unit, once part of
AT&T Network Systems, was spun-off from
Avaya in 2002 and became part of
CommScope •
iconectiv, formerly known as Telcordia and Bell Communications Research (Bellcore) Beginning in 1991, the
Baby Bells began to consolidate operations or rename their
Bell Operating Companies according to the parent company name, such as "Bell Atlantic – Delaware, Inc." or "U S WEST Communications, Inc.", to unify their corporate images. ==Legacy==