| 摘要 |
PURPOSE:To recover temporarily the disabled communication by transmitting the information on a designated key when no coincidence of keys is obtained between the transmission and reception stations, then controlling a descrambler of reception signals. CONSTITUTION:In case the communication is disabled due to a difference caused between key setting parts 4 and 21, the key set value is selected to a prescribed special key between transmission stations. In such a case, the key information is transmitted to a transmission line from a key information reading part 6 and a key information synthesizing part 5 respectively. While a switch part 19 is changed to an input A between reception stations after a key reception detecting part 14 detects said key information. Then the key information received by a key information extracting part 20 is given to a descrambler 13 through a transmission line. The descrambler 13 works in accordane with the output of the part 20. |
