Teletext systems expensive cost of NABTS decoders, costing in the thousands of dollars upon their release to the public. NABTS, however, was adopted for a short while by American TV networks NBC & CBS throughout the early-to-mid 80s, CBS using it for their short-lived ExtraVision teletext service, which premiered after the early Antiope & Ceefax trials by CBS & KNXT, and NBC, who had a NABTS-based service called NBC Teletext for a very short time in the mid-1980s. NBC discontinued their service in 1985 due to the cost of NABTS decoders not dropping to an affordable level for the consumer public. The
Teletext to four lines a frame. While the basic teletext format has remained unchanged in more than 30 years, a number of improvements and additions have been made. A closely related service is the Video Program System (VPS), introduced in Germany in 1985. Like teletext, this signal is also broadcast in the vertical blanking interval. It consists only of 32 bits of data, primarily the date and time for which the broadcast of the currently running TV programme was originally scheduled. Video recorders can use this information (instead of a simple timer) in order to automatically record a scheduled programme, even