| 摘要 |
PROBLEM TO BE SOLVED: To achieve a communication system that can prevent utilization of illicit time information operated by a user side.SOLUTION: The communication system is configured such that: an application sever 20 and a time server 10 are connected to a communication network; a user terminal 60 receiving service requiring the time information from the application server 20 connects with the communication network via a subscriber terminating device 50 and a station side device 40; and a time synchronization between the time server 10 and the subscriber terminating device 50 is established. In the communication system, the subscriber terminating device 50: includes a timer function 56 that operates at the time synchronization with the time server 10; determines whether a predetermined time elapses comparing with the time information from the timer function 56; and controls validation or invalidation of data transmitted and received through the own device based on a result of the determination. |
