| 摘要 |
PURPOSE:To reduce the communication time by preventing invasion of an incoming confluent noise from a subscriber terminal equipment side, eliminating non- response state to a polling from a center and decreasing an incoming carrier signal from the subscriber terminal equipment. CONSTITUTION:An incoming transmission line switch 9 provided to an incoming transmission line 13 is normally opened to interrupt all incoming signal including incoming confluent noise. A distributor 8 connects to a band pass filter 10 to distribute an incoming signal from each terminal equipment. The band pass filter 10 extracts a carrier signal with a fixed frequency from the distributed incoming signal and sends the signal to a rectifier 11. After the rectifier 11 rectifies the signal, the result is sent to the incoming transmission line switch 9 as a control signal. When the control signal is inputted, the incoming transmission line switch 9 is closed to send the incoming signal from each terminal equipment. |
