ExtraVision
ExtraVision, an over-the-air teletext service of CBS 
Television,
was the culmination of five years of effort by the Columbia Broadcasting
System.
It was launched in early 1984 using Antiope
technology. CBS had tested both Ceefax and Antiope systems at affiliates
including 
KMOX
in St. Louis and KNXT in Los Angeles as early as 1979, but it was held up
in going public by the Federal Communications 
Commission's
initial refusal to approval over-the-air teletext broadcasting.
Before launching ExtraVision, CBS also contracted
with a Los Angeles independent, KCET, to develop and test children's
educational programming.
ExtraVision tried to be a sort of national electronic magazine carrying
classified ads, airplane timetables, shopping information,
news and weather, using Samsung decoders.
It closed in 1988.