Abstract: In one embodiment of the invention, a conventional home computer is connected via the Internet to a link broadcasting computer that is being accessed by many other households. The link broadcasting computer receives the same television signals (including ATVEF signals or other datacast signals) received by the home televisions of the various users. The link broadcasting computer detects the ATVEF signals embedded in the vertical blanking interval of each television channel and communicates to each user's home computer only the ATVEF information for the particular television channel(s) previously identified by the user. The user can then access a website identified by the information. Various options are further described herein.

Abstract: An audiovisual subscription system includes means for aperiodically inverting the lines of a transmitted video signal of a frame-by-frame basis and for decrypting encrypted PCM audio information which is transmitted along with the aperiodically inverted video information.