| 摘要 |
PURPOSE:To simplify a circuit constitution by making the return setting signal generating device of a line terminal equipment and a return setting signal detecting device into one device respectively and using a return setting pattern outputted from an above-mentioned generating device for changing over a return setting switch and for measuring an error rate. CONSTITUTION:At the time of starting the measurement, a pattern, in which a return setting signal generating device 1 occurs, is sent from a line terminal equipment A of a measuring side. At a line terminal device B of the measured side, a receiving signal is inputted to a return setting signal detecting device 6, and a part of a pseudo random signal is detected. A gate circuit 8 comes to be the open condition when the terminal equipment B is the measured side. Consequently, the output of the detecting device 6 is added to a return setting switch 7 and the switch 7 is set to the return condition. At the terminal equipment A, the receiving signal is supervised by a generating device 3, and when a part of a pseudo random signal is detected, it is decided that the return is set. Thus, the measurement of the error rate is started by a measuring device 4. When a gate circuit 5, when the equipment B is the measuring side, is an open gate.
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