| 摘要 |
PURPOSE:To install a facsimile equipment regardless of the power source polarity of a telephone line by altering the content of a memory where a normal power source polarity is stored when a calling signal that is to be transmitted continually is not detected within a prescribed time. CONSTITUTION:With the indication of the transmission of an original, a processor 1 closes a contact point 7 through a circuit control circuit 5 and detects whether electric current is flowed or not to a diode D by the power source polarity of the telephone line by a photo coupler 6. The processor 1 collates a detecting signal with the data of a memory 3 and decides the state of the power source polarity. When the state is decided as an inversion, the contact point 7 is opened and a timer 4 is set and a contact point 9 is closed, and a calling signal with 16Hz that is inputted through a capacitor C is waited for. When the calling signal is inputted, it is decided as an incoming and a contact point 8 is closed and the reciving of transmitted data is processed. When an interrupt signal that represents time over from the timer 4 is received, the processor 1 alters the data for a polarity collating in the memory 3 and closes the contact pint 7, and goes through a polarity detecting operation at the time the interrupt signal is counted at n times.
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