Abstract: A television system with access control comprises a transmitter and receis. The transmitter comprises a video signal and sound signal formation circuit, means for transmitting these signals and a jamming circuit using a service key. Each receiver comprises means for receiving the transmitted signals, means for the display of the picture and for restoring the sound and an unjamming circuit connected to the reception means and working with the service key.It also comprises a subscription management center and in the transmitter a digital signal generator, a circuit for the formation of digital messages and a data broadcasting system and in the receiver a subscription card, an extraction circuit for the data, and a circuit for restoring the service key. There is also at least one subscription card loading station connected to the subscription management center.
Type:
Grant
Filed:
June 11, 1980
Date of Patent:
October 12, 1982
Assignees:
Etablissement Public de Diffusion Dit: Telediffusion de France, Gerard Babonneau
Inventors:
Claude Sechet, Gerard Babonneau, Louis C. Guillou