| 摘要 |
A buffer memory, an electrically erasable and writable ROM, a capacitor for holding voltage, and a voltage detection circuit for detecting the voltage of a battery for power source are provided in a portable telephone unit. During conversation, data to be conserved are written into the buffer memory. At time of clearing conversation, the data written in the buffer memory are transferred to a ROM and written therein. When the voltage detection circuit detects a fact that the voltage of the battery is unobtainable, the buffer memory and the ROM are operated and the data written in the buffer memory are also transferred to the ROM and written therein by the voltage held in the capacitor. <IMAGE> |
