| 摘要 |
A CATV terminal in which an on-screen video message is superimposed over the selected video program to indicate if the selected program is a pay per view, i.e., chargeable, program. The in-band data from the head end carries an event code designating whether the program is chargeable or not. If chargeable, a controller in the CATV terminal activates an on-screen video generator to generate an on-screen message announcing that the program is a PPV or chargeable program. This is superimposed on the program, which is not observable by the viewer until an authorization key is activated. An event code altered by noise or the like will have little adverse effect since the in-band event code has a period equal to the vertical period and the controller continuously controls the on-screen video generator.
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