AT&T (American Telephone and Telegraph) is one of the largest telecommunications providers in the United States. It is also noted for being the birthplace of the Unix operating system, and the C and C++ programming languages.[1]
History[]
AT&T was incorporated in 1885, but traces its lineage to Alexander Graham Bell and his invention of the telephone in 1876. As parent company of the former Bell System, AT&T's primary mission was to provide telephone service to virtually everyone in the United States. In its first 50 years, AT&T established subsidiaries and allied companies in more than a dozen other countries. It sold these interests in 1925 and focused on achieving its mission in the United States. It did, however, continue to provide international long distance service.[1]
AT&T logo in 2005.
The Bell System was dissolved at the end of 1983 with AT&T's divestiture of the Bell telephone companies. AT&T split into three parts in 1996, one of which is Lucent Technologies, the former systems and equipment portion of AT&T (including Bell Labs).[1]
Wireless services[]
Advancement of AT&T's wireless technology.
AT&T's 2G and 3G services were based on GSM and its derivative UMTS, respectively.[2] AT&T Wireless was the iPhone's first exclusive carrier until February 10, 2011, when rival carrier Verizon released a CDMA-capable iPhone 4, ending Apple's exclusivity agreement with AT&T.[3]
Apple devices exclusively carried by AT&T[]
Retirement of 3G service[]
AT&T shut down its GSM-based 3G network on February 22, 2022 to make room for faster 4G and 5G services.[4][5] This affected all older iPhone models that do not support Voice over LTE (iPhone 5C, 5S and earlier). This also affected the 3G-enabled original iPad and iPad 2.[6]
References[]
- ↑ 1.0 1.1 1.2 American Telephone and Telegraph, Inc. at the Free On-Line Dictionary Of Computing. 2002-06-21.
- ↑ AT&T GSM Network Technology (PDF), AT&T. 2008-05-20.
- ↑ Verizon Wireless Finally Gets Apple's iPhone by Sam Gustin, Wired. 2011-01-11.
- ↑ Act now - 3G is going away in 2022, AT&T. 2021-09-09.
- ↑ Plan Ahead for Phase Out of 3G Cellular Networks and Service, Federal Communications Commission. 2021-08-23.
- ↑ Devices Working on AT&T Network (PDF), AT&T. 2021-09-03.
External links[]
- AT&T official website
- AT&T Services apps at the Apple App Store
- AT&T at Wikipedia