BYPASS CONTROL CIRCUIT OF REPEATER

摘要

PURPOSE:To attain bypass control of a repeater only through a signal transmission line by providing a test control signalf detection circuit detecting a test control signal and a timer circuit started when the said circuit detects the test control signal and controlling a bypass setting switch to the inside of the said switch of the repeater. CONSTITUTION:The 1st and 2nd changeover switches S1, S2 are turnel on to a signal reproducing circuit REP at communication normally and a signal from a high-order station is inputted to the repeater via an input terminal T1. When a test control signal detection circuit DET receives the test control signal, the timer circuit TIM is started to throw the changeover switches S1, S2 to the bypass position. Thus, an input terminal T1 and an output terminal T2 are short- circuited in the repeater and it is possible to regard the repeater as a part of a transmission line electrically. Since the circuit TIM holds the switches S1, S2 until a prescribed time, it is not required to transmit the test control signal during the test. After a preset time is elapsed, the circuit TIM completes count, the changeover switches S1, S2 are thrown to the position of the signal reproduction circuit and the circuit is restored to the normal communication state.