Loading patent…
AssigneeScientific-Atlanta, Inc.
InventorsNigel Seth-Smith, Cameron Bates, Samson Lim, William van Rassel, Robert Yoneda, Keith Lucas
Estimating the term…
A subscription television system in which individual decoders are enabled to receive individually addressed messages is disclosed. The composite signal, including video and teletext, also comprises addressed packets which are detected by decoders and which indicate that a message addressed to a particular subscriber is forthcoming, and system control data. In a preferred embodiment, both addressed packets and teletext are encrypted. The addressed packet is decrypted using a decoder-specific code and a transmitted code, while the teletext message is decrypted using a decryption key contained in the system control data. The teletext message cannot be received until the addressed packet has been decrypted. Therefore, redundant levels of security are provided to the system. Messages for display to the user can be selected in response to user initiated commands, in response to decoder initiation, or in response to the transmitter.
A method of transmitting individual data in packets to plural decoders of a television subscription system, each decoder receiving the same addressed data packet, said method comprising the steps of:
A television subscription system capable of transmitting individual data to a plurality of decoders, the plurality of decoders being arranged individually or in banks of decoders, each decoder receiving the same addressed message, said system comprising:
Dependencies are inferred from the claim text.