| 摘要 |
PURPOSE:To monitor the status of built-in power source in a telephone set at arbitrary time, by providing a means discriminating whether an incoming signal from a station is a power supply status monitor instruction signal or a call signal. CONSTITUTION:When an incoming signal comes from a station via a line interface 5, this incoming signal is discriminated at a signal discrimination circuit 1, and when the signal is call signal, a control signal is given to a ringer circuit 2 from a discriminating circuit 1 to generate a call signal. When this incoming signal is a power supply status monitor instruction signal, a monitor signal is given to a power supply status information transmission circuit 4 from the circuit 1, resulting that the information representing the state of power supply is transmitted to the station from the circuit 4 via the interface 5. |
