| 摘要 |
PURPOSE: To issue a caution from a held alarm when the located position of portable cordless telephone set gets away longer than a prescribed distance. CONSTITUTION: When the portable cordless telephone set and the loss alarm are settled within the valid reception distance of radio waves of telephone set, the loss alarm receives these radio waves and a signal is detected through a high frequency amplifier circuit 10 and a frequency reduction circuit 20 by a detection circuit 40. According to this signal, the operation of caution integrated circuit 50 is suppressed. When they exceeds the range of valid reception distance, the signal is not detected any more. Therefore, no signal is inputted to the caution integrated circuit, a selected warning signal is generated by operating a warning mechanism, and the attention of user is called. Thus, the portable cordless telephone set can be prevented from being lost. |
