A control unit is inserted in the power lines that serve a vehicular telephone and an audio system. A power monitoring circuit detects current increases related to operation of the telephone, either from an incoming "ring" signal or the "off hook" condition in preparation for an outgoing call. The monitoring circuit generates a control signal which is applied to an electronic switching circuit that interrupts the flow of power to the audio system circuits. So long as the telephone is in use, the audio system is disabled. When the telephone returns to the quiescent or stand-by state, the current drawn by the telephone drops substantially below a threshold level of the monitoring circuit and the switching circuit restores the power to the audio system.
A base station (102) automatically remotes to a speakerphone mode of operation and connects an incoming call while an external electronic device (104) is simultaneously controlled.
A delay and inverting circuit, connected to the car phone system, is for delaying a status of operation of the car phone system and inverting a signal having a predetermined signal level according to the operation of the car phone system. A switching circuit, connected to the delay and inverting circuit, is for effecting a switching operation in accordance with a signal generated from the delay and inverting circuit. An amplifier, connected to the switching circuit and the car audio system, is for amplifying an output signal generated from the switching circuit and generating a driving signal to the car audio system.
A micro mobile phone battery charger for nickel hydrogen and lithium ion batteries, having advantages of high charging efficiency, quick charging, being adaptable for use with different voltages, and compactness. includes a casing, a rotary concealable charger plug, an internal circuit device, and battery terminals arranged to retain the battery in the housing and eliminate the need for lead wires. The internal circuit device, includes an overload, over-voltage protection circuit, an electromagnetic interference filter circuit, a voltage stabilizing circuit, an oscillation circuit, a direct current rectifying circuit, a car charge direct current input protection circuit, an alternating current filter circuit, a detection circuit, and an automatic power interruption system. The current is automatically adapted so that the input voltage range is from 90 to 250V to adapt to municipal currents of 110 to 240V and car charging.
An apparatus for use with a cellular telephone to indicate an incoming telephone call to a user includes a cellular telephone battery pack has a circuit that generates a voltage signal with a value representative of the current being drawn from the battery by the operation of the cellular telephone. A status determination circuit monitors the voltage signal and generates a waiting for call state signal whenever the value of the voltage signal decreases from a first selected higher value to a first selected lower value for a first preselected period of time. An incoming call detection circuit whenever the waiting for call state signal is present and either the voltage signal increases from a second selected lower value to a second selected higher value and remains at or above the second selected higher value for a second preselected period of time, or the current goes from a lower preselected current value to a higher preselected current value and remains at or above the higher current value for a third preselected period of time. An alarm is operative upon receipt of the alarm start signal for indicating an incoming call to a user. Also a cutoff circuit monitors the voltage of the battery and disables the apparatus further operation whenever the battery voltage drops below a preselected cutoff value to avoid damage to the battery.
An apparatus and method for indicating an incoming call that generates a voltage signal with a value representative of the current drawn by operation of the device. A circuit monitors the voltage signal and generates a waiting for call state signal whenever the value of the voltage signal decreases from a first selected higher value to a first selected lower value for a first preselected period of time. An RF detection circuit monitors the status of the device's transmitter and generates a transmitter active status signal whenever RF appears for a selected period of time. An incoming call detection circuit generates an alarm start signal whenever the waiting for call state and transmitter active status signals are present and either the voltage signal increases from a second selected lower value to a second selected higher value and remains at or above the second selected higher value for a second preselected period of time, or the current goes from a lower preselected current value to a higher preselected current value and remains at or above the higher current value for a third preselected period of time. An alarm, operative upon receipt of the alarm start signal, indicates an incoming call to a user. A circuit monitors the battery voltage and disables the apparatus whenever the battery voltage drops below a preselected cutoff value to avoid damage to the battery.
