| 摘要 |
PURPOSE:To conduct the pad test of an exchange in on-line by utilizing an idle line and conducting the test while a test tone is circulated in a loop circuit without disconnecting a subscriber terminal equipment especially and connecting a test equipment so as not to disturb the communication between subscriber terminal equipments during the operation of an exchange. CONSTITUTION:A test tone generating circuit 34 is connected to one input terminal of a multiplexer (MPX) 24 and a test tone generating circuit 35 is connected to one output terminal of a demultiplexer (DMPX) 29. A pad circuit 28, the (DMPX) 29, a conference operation circuit 33, the MPX 24 and a time division exchange circuit 26 form a loop circuit. Since a test tone is subject to prescribed attenuation by the pad circuit 28, number of circulations of the loop circuit for the test tone brought to be silent is obtained in advance and the test tone is circulated in the loop circuit for the number of circulations. Then the time division exchange 26 uses the DMPX 29 to allocate the test tone to a time slot distributed to a test tone reception circuit 35. When the test tone received by the test tone reception circuit 35 is discriminated to be silent, it is discriminated that the pad circuit 28 is operated normally.
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