| 摘要 |
PROBLEM TO BE SOLVED: To enhance the possibility of calling at the time of necessity by shifting a mode to a low consumption waiting mode where consumable current is reduced when a residual battery quantity becomes smaller than a first calling possible value in a waiting state and a call state. SOLUTION: A telephone set 10 is provided with a connection switch 30 for supplying the power source of the battery 29 and an A/D converter 31 converting the voltage VB of the battery 29 into a digital signal. The voltage value of the battery 29 is detected by output data of the converter 31, the value is compared with the voltage values V1 and V2(V1>V2) stored in ROM 32 which is incorporated in a microcomputer 11 and shifting, etc., to the low consumption waiting mode is controlled. When the voltage VB is the value, the voltage value V1 is set to be the one by which a call for a prescribed time, for example, more than two minutes after call is possible. The voltage value V2 is set to be the one by which a normal operation as a portable telephone set is guaranteed when the voltage VB is more than the value. |
