| 摘要 |
PROBLEM TO BE SOLVED: To provide a data communication system which minimizes probability of an incommunicable state due to the deterioration of a received data status by dynamically controlling an evaluation reference with which the received data status is detected. SOLUTION: In each of a center device 107 and a terminal device 108 which are connected through a bidirectional CATV network, state detectors 101 and 104 detect data status such as an error ratio and a signal level of received data from other devices, and when the detected data status deteriorates more than a threshold, a current transmission frequency of its own device is changed into, e.g. the frequency of the next channel, and at the same time, the transmission frequency of another device is requested to be changed so that the communication frequency of the devices 107 and 108 is changed to another frequency band. This makes it possible to automatically change a communication frequency and to immediately recover a communication status. |
