system to enable france to selective abonnentbasis - in a subscriber communication network

摘要

A system in a subscriber terminal of a subscriber communication network enables descrambling of a received scrambled signal on an impulse-purchase basis. A circuit processes a received cost signal and a received credit signal to determine whether the subscriber has sufficient available credit to pay for the descrambling, and then provides a credit-available signal when it is determined that sufficient credit is available. A circuit responds to the credit-available signal for indicating that the subscriber has the option of causing the scrambled signal to be descrambled. A circuit can be enabled to accept the option and provide an accepted signal. A circuit responds to the accepted signal to descramble the signal. A separately claimed system for descrambling on a prepaid basis involves comparing a received mask signal related to the scrambled signal with a received authorisation signal. This system is compatible with the impulse-purchase descrambling system.