PURPOSE: To start and terminate a call even in a place where a power voltage is not supplied by forming a closed circuit and transmitting a detected signal only when a slave unit is set in the prescribed position of a charger.
CONSTITUTION: When the slave unit 2 is mounted on the charger 1, contacts 1a, 1b, 1c are brought into contact with contacts 2a, 2b and 2c and a charge voltage V1 is supplied from a charge circuit 4, whereby a battery 6 is charged. At that time, the voltage V1 is given to a control part 13 as a detected signal. When the power voltage is not supplied to the charger 1, an output current flows from the battery 6 of the slave unit 2 to the negative terminal of the battery 6 through a power switch 12, a three terminal regulator 11, the contacts 2c, 1c, 1b and 2b and a resistor 9. Thus, the output voltage V2 of the regulator 11 appears in a connection point 10 and the control part 13 judges that the slave unit 2 exists in the charger 1 with the output voltage V2 as the detection signal. Thus, the call can be started and terminated in a case when the power voltage is not supplied or in the place where power cannot be obtained.
TODA MANABU
ONO KOJI
