Abstract: The invention provides a control information format construction used in image information transmission in a system combining a facsimile device and a computer, having: a head code of one byte for showing start of the control information; a control code of one byte located at just after the head code, including an operation mode control information, a manuscript mode control information, an end control information, and a response control information for error, for showing the kind of control; and a control end code of two bytes located at just after the control code, for showing end of the control information.

Abstract: The invention provides a computer connection circuit in a facsimile, comprising: control and memory unit including CPU(Central Processing Unit)(11a), RAM(Random Access Memory)(11c), and ROM(Read Only Memory)(11b) for controlling a general operation control of the facsimile; address decoder 12 connected to the control and memory unit through an address bus, for selecting and enabling an output terminal according to an input address; a modem 31 connected to the control and memory unit through a date bus and connected to communication lines, in which is driven by a first chip selection signal of the address decoder 12 and requires an interrupt to the control and memory unit in sending/receiving image information; and an UART51(Universal Asynchronous Receiver & Transmitter) connected to the control and memory unit and to RS232C interface means of the computer, in which requites an interrupt to the control and memory unit in sending/receiving image and character information to/from the computer and is driven by a