| 摘要 |
PURPOSE:To prevent the useless operation or a malfunction of a switchboard, by informing a fault of a data highway to the switchboard as a disconnection of subscriber. CONSTITUTION:For an originating call given from a subscriber 4, a loop is formed by a terminating circuit 12 of a common terminal repeating device 2 to a switchboard 1 via a subscriber line 6. With an incoming call to the subscriber 4, a call signal is transmitted to the line 6 from the switchboard 1. Then the call signal received at the circuit 12 is multiplexed by the device 2 and transmitted to a data highway. If the data highway has a fault, this fault is detected by a fault detecting circuit. Then an alarm signal supplied to a terminal 14 is set at ''0'', and a transistor 13 is turned off. As a result, a relay 11 is restored and contacts 10a and 10b of a switch circuit are broken. That is, the line 6 is cut off and no call information is transmitted to the switchboard 1. At the same time, the call signal given from the switchboard 1 is not transmitted to the subscriber 4. |
