| 摘要 |
PURPOSE:To detect a fault of a dial sending circuit and a charging signal reaction circuit by providing a counter counting in response to hooking and reset by an output of the charging signal reception circuit and a discriminating means discriminating that the count reaches a prescribed value. CONSTITUTION:When the execution of a program transfers to hooking processing, a CPU 111 restores a GS relay 103 via a restart circuit 102 at first to open a DC loop thereby restoring an exchange. After 1,200ms is elapsed, after the CPU 111 confirms that on-hook is consecutive, the CPU 111 checks whether or not a flag representing the reception of a charging signal in a prescribed area in an RAM of the 1st memory 114 is set and when no flag is set, the count of a check counter of the 2nd memory 112 is incremented by 1. As a result, when the counter reaches '50', the CPU 111 discriminates it as an error, applies alarm sending processing to inform the error to the center and resets the check counter.
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