From its origins in 1875 to 1984, AT&T ran the Bell System, the US telephone monopoly. In the computer industry, the company is best known for the work carried out at its Bell Telephone Laboratories. In 1984, the company was broken up into eight companies (the new AT&T itself and seven regional operating companies), following an agreement with the US Department of Justice. In 1991, AT&T acquired the computer company NCR; other acquisitions followed. In 1996, however, a major restructuring took place in which AT&T split into three companies, a systems and equipment company (Lucent Technologies), a computer company (NCR), and a communication services company (AT&T itself). AT&T was bought by SBC Communications, Inc., in 2005, which then renamed itself ‘AT&T Inc’.