| 摘要 |
PROBLEM TO BE SOLVED: To provide a data transmission system which safely and further surely realize data transmission from a data transmitter to a data receiver. SOLUTION: A data transmission 1 has a data transmitter 2 which performs encipher and transmits data, data receivers 3a to 3c to which enciphered data are distributed from the transmitter 2, satellite channels 4a which are used to transmit data from the transmitter 2 to the receivers 3a to 3c and two-way communication paths 9 which are also used to transmit data from the receivers 3a to 3c to the transmitter 2 and whose data transmission capacity is smaller than the channels 4a. The channels 4a are used to transmit enciphered data from the transmitter 2 to the receivers 3a to 3c and the paths 9 are at least used for communication of data limitation transmission control information between the transmitter 2 and the receivers 3a to 3c. |
