Method for facilitating a dialog between a subscriber to a pay television system and a decoder of the received signals, and a decoder for these signals

The decoder includes a microprocessor (11) connected to a teletext data receiver (10) and a text generator (14) for the television screen. In addition, a card (12) known as CPTV is associated with the microprocessor (11), this card managing the credit necessary for the purchase of programs, storing purchased programs and allowing descrambling of the programs purchased by sending to the microprocessor of the entry point in the sequence that it calculates using information that it has memorized as well as those it receives from the decoder. The scheduled programs are sent by the head station and stored in the microprocessor (11). Another memory thereof memorizes manipulation instructions to be made to select a program and the buy as well as to recharge a credit on the CPTV card. A keyboard (13) makes it possible to select and display on the television screen the planned transmissions as well as the handling instructions, which greatly facilitates the dialogue between the user and the decoder and helps to avoid handling errors. The decoder according to the invention functions as a user guide for all operations to be performed