Digital information signal transmitting/receiving method and system

摘要

A digital information signal transmitting/receiving method and system having a transmitter for transmitting an encrypted digital information signal and a plurality of receivers for receiving the encrypted digital information signal from the transmitter. The transmitter simultaneously distributes a plurality of identification codes associated with the receivers at a time ahead of the digital information signal. The receivers detect whether a particular identification code assigned to the receiver was included within a received plurality of identification codes. When the particular identification code has been detected as having been received the received encrypted digital information signal is decrypted into the original digital information. In order to request that a particular identification code be included so as to allow access to a program, either one of the receivers or the recorders each generate an information request signal. The transmitter is responsive to the information request signals to add to the digital information signal at a time ahead of the digital information signal, identification signals for identifying the receivers or the recorders which generated the information request signals, thereby producing a transmission signal formed of those signals, and to distribute this transmission signal to the receivers. The recorders control the received information signal to be recorded in response to the identification signals received by the receivers.