CONTROL SYSTEM FOR LOOPBACK TEST FOR TRANSMISSION LINE

摘要

PURPOSE:To attain loopback test of plural devices with one kind of test code by providing a timer set by a test code detected at a forward line and reset by a test code detected at a return path into each device. CONSTITUTION:A test code from a test device 8 is sent through a forward path 6 and subject to loopback to a return path 7 through an intra-office equipment 9, repeaters 10, 11 and a subscriber's equipment 12. The test code is received by the equipments 9-11, detected by a detection circuit 1 of each equipment to start a timer 2. On the other hand, the test signal subject to loopback through the return path 7 is detected by the detection circuit 3 of the equipments 9-11, then a timer 2 is reset. On the other hand, if a detection circuit which does not detect a test code being subject to loopback exists, then the timer 2 is in time-over and the test codes of the number set at each equipment from a test code transmission circuit 4 are reflected to the return path 7 via a switch 5. The test device 8 detects the number of the test codes to recognize the equipment set by loopback.