At+t Corp.

Bell Telephone Laboratories

Stephen Gratzer McWilliams

Jack E James

Byron Lynn Johnson

Michael Wyndham Heller

Ronald Lee Katz

Apparatus for interdicting television channels of a cable television system comprises a plurality of oscillators dedicated to jamming the audio portion of television channels to be interdicted, and a further plurality of different oscillators dedicated to jamming the video portion of television channels to be interdicted. The number of jamming oscillators for jamming the audio is less than or equal to the number of jamming oscillators for jamming the video. The hopping rate for video jamming is greatly in excess of the hopping rate for audio jamming. On the other hand, the dwell time for audio jamming is greatly in excess of the dwell time for video jamming. At least two levels of jamming effectiveness of both audio and video portions can be addressably controlled from the headend of a system including such interdiction apparatus. If shared oscillators according to prior art techniques are used to jam both audio and video, this form of jamming engine may be selectively actuated in preference to or as an alternative for a jamming engine comprising both an audio jamming oscillator and a video jamming oscillator.

Method and apparatus for interdicting cable television channels

In an automatic remote meter reading system, a tamper protection circuit (101) provides an alarm signal at a central station upon the disconnecting or tampering with a remote utility meter (100). Tamper protection is provided for the meter and for the transmission line carrying energy usage information to a transponder (500) such that any interruptions of the circuit path causes an alarm to be generated. The circuitry includes a remote resistance (132) associated with each meter to be protected. The value of the remote resistance is continually compared with a resistance (110) having a given value within the tamper protection circuit such that for any changes in the value of the remote resistance, an imbalance in the tamper circuit occurs and the alarm signal is generated.

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Greenwood, IN, United States of America

Stephen Gratzer McWilliams