Originally the company was called Tele Centro Sul, because its service covered the states in the central and southern parts of Brazil, namely Acre, Rondônia, Goiás, Tocantins, Mato Grosso, Mato Grosso do Sul, Paraná, Santa Catarina and Rio Grande do Sul, as well as the Distrito Federal.

The Brazilian investment bank Opportunity, which managed funds for investors including Citigroup and some Brazilian pension funds, in partnership with Telecom Italia, paid 2.07 billion reais in June 1998 to buy Tele Centro Sul from the Brazilian government as part of the privatization process of Telebrás.

In 2001, the company purchased a small stake in the iBest Co. website and launched a portal and free internet access service; at the time, the Marcos Wettreich was the main shareholder in iBest.

[2] That transaction required changes in legislation, since legislation at the time prohibited a fixed telephone company from purchasing another fixed telephone company in a different license area.

That legislation has since changed, and Oi completed its purchase of BrT on January 9, 2009.