In an image input/output system, an image input/output control apparatus is interposed between an image input/output apparatus and an information terminal apparatus. Data exchange is performed between a first transmitting/receiving section of the image input/output control apparatus and a transmitting/receiving section of the image input/output apparatus as well as between the second transmitting/receiving section of the image input/output control apparatus and a transmitting/receiving section of the information terminal apparatus. The first transmitting/receiving section and the second transmitting/receiving section are isolated from each other physically. Under the control of the control section of the image input/output control apparatus, data received by one of the first transmitting/receiving section and the second transmitting/receiving section is transmitted by the other. User interfaces relating to image input/output of the image input/output apparatus are provided by a user interface providing section of the image input/output control apparatus.