| 摘要 |
PURPOSE:To prevent a signal from being overlooked at a transmission side by providing a device measuring an echo time of a transmission path, and controlling the receiving operation by means of the device. CONSTITUTION:An echo of a transmission signal of the own device returned from communication lines 1, 2 and a signal from an opposite device are transmitted to a receiver 5 via a transmission/reception switching relay 3, demodulated and transmitted to a CPU via a signal line R. This signal is written in a reception signal memory and the content is compared with a transmission signal memory. Further, the transmitted signal train and the received signal train are repeated for the longest preset echo time. As a result, when a coincident data train is found out, the echo time is calculated and when the time is longer than the set time, since the data is used as the data having the longest echo time, the data of the echo time in the program memory is rewritten. |
