Oi is a telecommunications company that was generated from the sale of the state-owned Telebras in 1998, when it received the name of Telemar and would only in 2007 rebrand itself to Oi - Since 2002, Oi offers mobile telecommunication services and since 2005 it offers Internet services.

While this company has always been a giant of the sector, they have always had the improvement of the network as one of the central objectives in order to keep their customer network always satisfied - They also support a wide variety of cultural venues in general such as museums, show houses and theatres.

Nowadays they have a landline and mobile phone network, offering also 4g mobile internet, cable internet including optic fiber connection in some places and TV plans - Most people who opt for Oi's services look for the combinations between these services, which often come with a discount when compared to the price of the isolated services.