SELECTIVE INTERDICTION OF TELEVISION CHANNELS

摘要

With the present decoder/interdiction device combination (566), the microcontroller (518) receives authorization data from a data receiver (568) via its data output (570) that has been inserted at the headend to identify authorized subscribers (preferably identified with a predefined subscriber or box code in the microcontroller (518). The same microcontroller (518) that controls the common decrypting of a commonly encrypted input source (572), loads the channel interdiction table (516) according to the authorization data, e.g., according to tiers. The data in the interdiction table (516) is then used to control the operation of the frequency synthesizer/VCO (516) and the mute switch (522) using the control interface (528) and mute control signal (534) according to the previously described algorithm. This improved combination now permits the simultaneous reception of multiple unencrypted signals (suitable for picture-in-picture use) while still permitting the provider to withhold access to selected channels.