说明：  工业控制及测量领域较为常用的网络之一RS-485。本例通过485总线实现主从机之间的通信、数据传输及控制。程序是用C语言实现。内有详细解释，可读性和移植性强。
(industrial control and measurement field is one of the commonly used network RS-485. 485 cases through the realization of the main bus from the plane between the communications, data transmission and control. Procedure is used C language. Are explained in detail, readability and portability strong.)