ExtraVision
From Wikipedia, the free encyclopedia
ExtraVision was a short-lived teletext service created and operated by the American television network CBS in the early-to-mid 1980s. It was carried in the VBI of the video from local affiliate stations of the CBS network. It featured CBS program information, news, sports, weather, even subtitling for CBS programming (much like page 888 in British/European teletext, and American closed captioning). ExtraVision could also have its pages customized by the local affiliate station carrying it, for such things as program schedules, local community announcements, and station promotions.
ExtraVision was discontinued by CBS towards the end of the 80s, due to the service using the NABTS protocol, which required a quite expensive decoder to receive the service. Also, most of the local CBS affiliates carrying the ExtraVision service didn't bother to invest in the computer equipment required to customize pages to carry locally-oriented information on the service.
