This was the first version of the Videocipher system that was first demonstrated by Linkabit in 1983. Also known as Videocipher IB, this variation on Videocipher was commonly used by sports backhauls. CBS used this system from 1987 to the mid-1990s to encrypt its transmissions to affiliates on the Telstar 301 and Telstar 302 satellites. In Canada, the CTV television network also used this technology on its network feeds. With this system the video is scrambled by means of re-ordering the video scan lines, while all audio remains in the clear. This system was in use as late as the early 2000s. Videocipher I (VCI) system was initially considered for use by HBO in the 1980s. HBO tested VCI extensively, but was ultimately rejected in favor of Videocipher II. HBO's use of VCI would have required descramblers for home satellite viewers. Due to costs involved with VC1, maintaining VCI a descrambler was determined to be too expensive for consumer use. PBS in the USA used VideoCipher I on its satellite feeds to its member stations in the mid-80s to take advantage of the high-fidelity digital audio capability offered by VCI. This was desirable for some of the programming PBS would air in that era, such as classical concerts and other musical programming, some of which were simulcast by partnering public radio stations using the same audio feed. PBS had attempted in 1979 to send its program audio digitally to its member stations using a system called DATE (Digital Audio for TElevision), which used the existing analog video's vertical blanking interval (VBI) to send digital audio. VCI provided this same feature while freeing up the VBI for other purposes like closed-captioning and teletext, making DATE obsolete by the mid-1980s (however, DATE did offer 4 channels of audio as opposed to VideoCipher I's 2-channel stereo). The Leitch Viewguard scrambling system used for satellite feeds as well used the same video line re-ordering as well, while also leaving the audio intact. ABC and Fox used Viewguard as well on their analog network feeds to their affiliate stations shortly before switching to digital satellite distribution in 2005 (for ABC) and 2004 (for Fox). Videocipher II Videocipher II was the first consumer TVRO scrambling system. HBO and Cinemax, which had transponders on Satcom 3R and Galaxy 1, began encrypting their west coast feeds services with Videocipher II 12 hours a day early in 1985, then