| 摘要 |
PURPOSE:To transmit information to a trunk circuit without providing an exclusive loop information switch matrix for subscriber, by providing a means detecting a DC potential of a spatial split channel switch to a trunk circuit. CONSTITUTION:The loop information of subscribers is picked up as a change in a DC potential at a point A with an operational amplifier 14 via a photocoupler 9. When a CMOS analog switch 17 is closed, the potential change at the point A is transferred to a point B. The DC potential at the point B is monitored throug the comparison with a reference potential 10 at a comparator 15 and drives a detetion relay DET via a logical circuit 18. As a result, the subscriber loop information is transferred to a main trunk TRK. When the CMOS analog switch 17 is closed, a voice signal is communicated in the same path conventionally. |
