| 摘要 |
PURPOSE:To widely decrease a device internal interface cable by separating a line changing-over circuit having a redundant constitution and a line interface circuit, multiplex-transmitting the division by the time division and further, providing the changing-over circuit on a multiplexing signal. CONSTITUTION:At data exchange devices 11 and 12 equipped with the duplexing redundant constitution, a signal 14 from a line control circuit 13 is a line number 113, and connected directly to a selecting circuit 17 of a line interface circuit 16. A signal group 18 of circuit numbers 105 and 108 from the line control circuit 13 is multiplexed to a multiplexing signal 110 and inputted to a selecting circuit 111 by a time division multiplexing circuit 19. For selecting circuits 17 and 111, a data exchanging device 11 or 12 is selected by the instruction of a changing-over signal 112 and outputs 113 and 114 are generated. The output 114 is a multiplexing signal, and therefore, the output is inputted to a separating circuit 115 to return it to the originals signal line, and the separating circuit 115 restores a transmitting signal group 116 and outputs it. The output 113 and the transmitting signal group 116 are transmitted to MODEM by an electric level converting circuit 117.
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