Through the 1970s, the CRTC had established the principle of allowing cable television companies to carry "three-plus-one" from a nearby American city: the three commercial networks plus PBS. Cable companies further from the border, if they could offer this, had to use microwave, while many more could not afford to do so at all. In 1982, CANCOM proposed adding additional radio signals and four additional television stations, originating in the United States, in order to bring the American "three-plus-one" package to all Canadians. The CRTC approved and, on 1 September 1983, CANCOM began transmitting the four Detroit affiliates of the three major commercial networks and PBS: WJBK-TV, WDIV-TV, WXYZ-TV and WTVS. Cancom was a world leader with its pioneering technical expertise (including the first commercial and consumer applications of digital encryption for satellite TV distribution), and the first carrier to offer consumers direct broadcast satellite (DBS) services.