ExtraVision
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.
CBS had begun tests in 1979 using the French Antiope
system, and again in 1981 in the Los Angeles area. The full ExtraVision service began in 1983, and went nationwide in 1984. It was cancelled in 1986, a year after teletext had also been abandoned by NBC.
Teletext
Teletext is a television information retrieval service developed in the United Kingdom in the early 1970s. It offers a range of text-based information, typically including national, international and sporting news, weather and TV schedules...
service created and operated by the American television network
Television network
A television network is a telecommunications network for distribution of television program content, whereby a central operation provides programming to many television stations or pay TV providers. Until the mid-1980s, television programming in most countries of the world was dominated by a small...
CBS
CBS
CBS Broadcasting Inc. is a major US commercial broadcasting television network, which started as a radio network. The name is derived from the initials of the network's former name, Columbia Broadcasting System. The network is sometimes referred to as the "Eye Network" in reference to the shape of...
in the early-to-mid 1980s. It was carried in the VBI
Vertical blanking interval
The vertical blanking interval , also known as the vertical interval or VBLANK, is the time difference between the last line of one frame or field of a raster display, and the beginning of the first line of the next frame. It is present in analog television, VGA, DVI and other signals. During the...
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
Closed captioning
Closed captioning is the process of displaying text on a television, video screen or other visual display to provide additional or interpretive information to individuals who wish to access it...
). 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
NABTS
NABTS, the North American Broadcast Teletext Specification, is a protocol used for encoding NAPLPS-encoded teletext pages, as well as other types of digital data, within the vertical blanking interval of an analog video signal...
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.
CBS had begun tests in 1979 using the French Antiope
Antiope (teletext)
Antiope was a French teletext standard in the 1980s. It also formed the basis for the display standard used in the French videotex service Minitel....
system, and again in 1981 in the Los Angeles area. The full ExtraVision service began in 1983, and went nationwide in 1984. It was cancelled in 1986, a year after teletext had also been abandoned by NBC.
