CUSTOMER STATION SYSTEM INTERFACE FOR INTERNATIONAL SDN SUBSCRIBER TOLL DIALLING NETWORK

摘要

PURPOSE:To distribute directly a terminal device at a network termination by providing a competitive control circuit which controls a receiving circuit with a D-bit split function, a D bit folding circuit and an output frame circuit. CONSTITUTION:An input frame signal from a subscriber's bus 30 is received at a receiving circuit 2 through an incoming line 32 and the receiving circuit 2 splits a D-bit and outputs to a terminal a. One of the outputted D-bit is input ted to a d-bit folding circuit 4 and the other D-bit is inputted to a competitive control circuit 3. When an access request for channel D exists and also an incoming data detects the continuation of logic 1, the competitive control circuit 3 outputs a ready signal R. By this ready signal R, the D-bit is outputted from the terminal b of a man-machine interface 14 in a terminal device 10 which is connected to a network termination 20. This D-bit is selected by the signal R and is outputted to, as an echo bit, the suhscriber's bus 30 through a transmis sion circuit 1.