In this paper, a scheme about background communication between one microcomputer and others by IBM-PC/XT and XENIX is introduced, The softwares and the main points of technology are described.

The regression equations of expiratory and inspiratory resistances were built with multiple stepwise regression analysis on the IBM PC/XT computer with age, height and FVC as independent variables.

This paper briefly gives principles of using PRBS and step signal to identify system and describes methods of constructing IBM-PC/XT-computers identification system.