| 摘要 |
PURPOSE:To confirm the condition of an interrupting request of on-hook and off- hook, and to execute exactly an interruption in accordance with on-off information of a hook switch by providing plural FF circuits, a controlling circuit and a logical circuit. CONSTITUTION:At the time of calling of a digital telephone device, a switch S1 of a hook switch FS is set to off, a switch S2 is turned on, and by the supply of an office power source, a processor CPU executes an initializing processing, and initializing information is sent to a controlling circuit CONT. An FF1 is set, and an FF2 is reset by otuputs (a), (b) of this circuit CONT and charging of a capacitor C1. A set output of this FF1 and a reset output of the FF2 are provided to AND circuits A3, A4, respectively. Also, off-and-on hook outputs of the switches S1, S2 are provided to the circuits A3, A4. In such a way, the condition of an interrupting request of on-and off hooks is confirmed by the circuits A3, A4, supplied to the CPU through buffer circuits BF1, BF2, respectively, and interruption is executed exactly. |
