Rádio e Televisão de Portugal, S.A. is the public service broadcasting organization of Portugal. It operates four national television channels and three national radio channels, as well as several satellite and cable offerings.The company came into effect on 31 March 2004 with the merger of two previously separate companies Radiodifusão Portuguesa (RDP; the radio broadcaster) and Radiotelevisão Portuguesa (television broadcaster).RTP is a state-owned corporation funded by television advertising revenues, government grants, and the taxa de contribuição audiovisual (broadcasting contribution tax), which is incorporated in electricity bills.HistoryRadioThe Emissora Nacional de Radiodifusão was established on 4 August 1935 as the public national radio broadcaster, inheriting the previous broadcasting operations of the national postal service, Correios, Telégrafos e Telefones . Five years later, ENR became independent of the CTT.ENR was one of the 23 founding broadcasting organizations of the European Broadcasting Union in 1950. Following the Carnation Revolution, ENR was reorganized and in 1976 changed its name to Radiodifusão Portuguesa . During this process, several previously private radio stations – such as Rádio Clube Português – were nationalized and integrated into RDP.In 1979, the RCP network was rebranded as Rádio Comercial, and was later privatized in 1993. At the same time, RDP launched the youth-oriented radio station Antena 3 and abolished advertising from all of its stations, so that the aforementioned broadcasting contribution tax became its sole source of funding.