NABTS
From Wikipedia, the free encyclopedia
NABTS (North American Broadcast Teletext Specification) is a standard & protocol utilized for the encoding of NAPLPS-encoded teletext pages, as well as other types of digital data, within the VBI (vertical blanking interval) of an analog video signal. It is classified under standard EIA-516, and has a rate of 15.6 kbit/s per line of video (with error correction).
NABTS was originally developed as a protocol by Norpak for the delivery of NAPLPS-encoded teletext service in the USA and Canada, with other standards as WST (World System Teletext, aka World System 1) being used for teletext in the United Kingdom and the rest of Europe (WST was used in the USA briefly as well for some teletext services such as Electra). NABTS was the standard used for both CBS's ExtraVision and NBC's very short-lived NBC Teletext services in the mid-1980s.
Due to teletext in general not really catching on and being successful in the US, NABTS saw a new use for the datacasting features of WebTV for Windows, under Windows 98, as well as for the now-defunct Intercast system.
However, NABTS is still used for private closed-circuit data delivery over a television broadcast or video signal, and Canadian company Norpak (one of the developers of NABTS) still sells and manufactures encoders & decoders for NABTS.
