| 摘要 |
PURPOSE:To invalidate data modification at a transmission line, to prevent illegal dubbing and to strengthen protection against a copyright by adding error correction code to dubbing control information and main data and supplying it to the line. CONSTITUTION:A dubbing deciding circuit 66 reads dubbing times control code 61 included in data supplied through a transmission line D and decides whether data to be controlled is an object to be protected against a copyright or not. Further, if it is the object to be protected, it compares dubbing times recorded in the code 61 with predetermined dubbing times. If the recorded times exceed the predetermined times, it outputs an error signal to a controller 68 to inhibit data transmission to a record system. If it is less than the predetermined times, it outputs an allowance signal to the controller 68 to allow data transmission to the system. |
