PURPOSE: To remove waste of processing time and to make a response time earlier by transferring display data from a buffer to a terminal only when a transfer data buffer is full or only when a system side requires an input from a terminal side.

CONSTITUTION: A data transfer control system is composed of a pattern processing system I which consists of a pattern processing application part 1, a transfer data stack processing part 2, a transfer data buffer 3, a transfer processing part 4 and an input data reading processing part 6, and a terminal II and a terminal controller 5 which consist of a display 7, a tablet 8 and a keyboard 9. Only when the transfer data buffer 3 is full, or only when the pattern processing system I side requires an input from the terminal II side, the display data are transferred from the buffer 3 to the terminal II.