| 摘要 |
PROBLEM TO BE SOLVED: To provide the device for preventing unauthorized use of a cable communication system where an unauthorized reception terminal (decoder) is recognized, identified and excluded. SOLUTION: In a cable communication system (personal computer PC on line system) adopting the two-way digital communication system provided with a collision avoidance function against occurrence of packet collision, a high accuracy delay control function and a level control function for channel connection procedure, a signal converter SCS7 applies delay control or level control to a transmission packet from a terminal PC cable box PCX 8 or 8'. Then based on a control variable and registration data of the SCS 7, a clone terminal using illegally the PC on line system is confirmed, identified and excluded. |
