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You must modify your TiVo to install TCS. The TiVo series 1 is easily modifiable, the tivo series 2 takes a bit more effort. TCS works best on a series 1, as there are issues doing on screen displays on a series 2. TCS will not work on software versions 4.0 or higher, as there is no way (as of yet) to tap into the keypresses of the remote.
Find out how to extend the capabilities your TiVo and my favorite tivo extension programs