| 摘要 |
An emergency cellular telephone includes a low power timer which receives power directly from the battery and runs continuously. The timer periodically initiates battery tests and, if appropriate, low battery warnings, while the telephone is in an OFF state. The timer "wakes up" (powers-up) the telephone at a predetermined interval (for example, once per day or once per week). After each timer-controlled "wake-up", the processor performs a test to estimate remaining battery capacity (by measuring battery voltage with a load on the battery or other conventional battery charge monitoring techniques). If the remaining battery capacity is adequate, the telephone processor turns off and the timer is re-started. If the remaining battery capacity is low, a warning is issued. The low battery warning may use conventional methods, such as an aural or visual warning from the phone. Additionally, the warning may consist of an automatic wireless telephone call to a predetermined number which is loaded into the telephone by the user or carrier via the keypad and/or a system connector. The number called can be the user's land line number, another cellular number or a carrier number. The warning sent via the phone call can consist of audible tones, combination of tones, voice synthesized message or data. |
