摘要 |
In a matrix switch apparatus with a diagnosis circuit, a switch unit is positioned between a group of input line interface circuits and a group of output line interface circuits. The switch unit includes front switches and back switches, respectively, equal in number to the input and output line interface circuits, and middle switches of 2M in number. The number M is the number of interface elements included in each of the input and output line interface circuits. Each of the front and back switches is provided with input and output ports having a ratio, respectively, determined by (M+1) and 2M, and each of the middle switches is provided with input and output ports, respectively, equal in number to 2M. In accordance with the above structure, the diagnosis of a stand-by port connected to a stand-by interface element included in each of the input and output line interface circuits can be carried out, even if all working input and output ports connected to the interface elements are occupied for operation.
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