| 摘要 |
PURPOSE:To monitor a digital trunk through simple operation by providing a time-division switch with a monitoring circuit equipped with an input and an output terminal, and by extracting a monitoring signal by converting a digital signal into an analog signal by the monitoring circuit. CONSTITUTION:The up terminal A and down terminal B of the origination side of a time-division switch 7 are connected to an incoming trunk 1 through an encoder-decoder 3, and the up terminal C and down terminal D of the termination side of the switch 7 are connected to an outgoing trunk 2 through an encoder-decoder 4. Then, a monitoring circuit 8 equipped with terminals 1 and 2 is connected to the switch 7 to monitor a call being made, and in this case, the switch 7 connects the terminal A to the terminal 1 and the terminal C to the terminal 2. Digital signals sent from the terminals 1 and 2 to the circuit 8 are converted into analog signals by encoder-decoders 5 and 6 and those signals are synthesized by a voice synthesizing circuit 9, thereby monitoring trunks 1 and 2 through simple operation. |
