| 摘要 |
PURPOSE:To obtain a hotel vendor system capable of communicating at any time with small power consumption of a battery by turning a microcomputer to a stand-by state at the time of power failure and applying an wake-up signal by a command from a central controlling device. CONSTITUTION:If a commercial AC power supply is stopped and the output voltage of a rectifier circuit disappears, a signal indicating the power failure is applied to the terminal 1a of the microcomputer 1 to bring the microcomputer 1 to the stand-by state and a voltage is applied from a buttery 5. When a communication line 8 is brought to the low level by a signal from a front machine, transistors (TRs) 13, 17 are turned on, a light emitting diode of a photocoupler 15 lights up and a phototransistor 18 is turned on to charge a capacitor 23. After the lapse of a prescribed time, the output of an inverter 26 is brought to the low level and an interruption signal is applied to an interruption terminal 1c of the microcomputer 1 to bring the microcomputer 1 to the wake-up status. Consequently, the microcomputer 1 can communicate with the front machine. |
