| 摘要 |
PROBLEM TO BE SOLVED: To provide an inexpensive portable telephone set capable of coping with the momentary failures of the power source of the portable telephone set operated by a built-in battery or the drop of a battery residual amount. SOLUTION: The main body 17 of this portable telephone set is provided with a battery 13 and the cattery 13 is accessed through a freely openable and closable battery cover 15. The opening and closing of the battery cover 15 are detected by a battery cover opening/closing detector 1 or a battery cover opening/closing detection switch 18 inside the main body 17 and outputted through a control circuit 5 to a CPU 7 as interruption signals 6. Also, when the battery residual amount becomes small, battery residual amount detection signals 4 are outputted through the control circuit 5 to the CPU 7 as the interruption signals 8. Then, when the battery cover 15 is opened or the battery residual amount drops, the storage data of a RAM 11 are transferred to a FLASH ROM 10 and stored and protected. |
