| 摘要 |
PROBLEM TO BE SOLVED: To provide a distribution type channel switching system that realizes selection of wires telephone channels without the need for a commercial power supply. SOLUTION: In the distribution type channel switching system where terminals 301...30N using telephone lines in common are connected in series, a center unit 4 selects a terminal by a telephone number at first and then selects it by an identification number among the terminals 301...30N. Thus, the center unit 4 is connected to a specific terminal. In the case of making a call from the terminals 301...30N to the center unit 4, the communication is started after confirming that other terminal is not busy. When the other terminal is busy, the communication is started after the end of the communication. Furthermore, in the case that the communication with an i-th terminal is not available, a fault location is located by trying the communication with an (i-1)th terminal.
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