Facsimile system control apparatus

An apparatus for controlling a facsimile system comprising a main power supply, an auxiliary power supply, switch means for controlling the on/off condition of said auxiliary power supply, a first central processing unit (CPU) to which power is supplied from said main power supply which is turned on only during the operation of transmitting or receiving image signals and a second central processing unit (CPU) to which is normally supplied power from said auxiliary power supply when turned on by said switch means, whereby said second CPU monitors in a monitoring mode the condition of the facsimile system while it is in a stand-by state and in response to a command signal for the initiation of transmission or reception of image sigsnals or a telephone calling signal, said second CPU causes said main power supply to be turned on thereby causing said first CPU to be operatively connected to said main power supply and making said second CPU functionally dependent upon said first CPU whereas, upon completion of the transmitting or receiving operation, said second CPU causes said main power supply to be turned off thereby causing said first CPU to be operatively disconnected from said main power supply in response to an instruction signal supplied from said first CPU, thereby reestablishing the monitoring mode, and, wherein said first CPU supplies an inquiry command signal to said second CPU upon being connected to said main power supply, said inquiry command signal inquiring as to the causes of the connection to said main power supply.