说明：  串行口是计算机一种常用的接口，具有连接线少，通讯简单，得到广泛的使用。常用的串口是RS-232-C接口(又称EIA RS-232-C)它是在1970年由美国电子工业协会(EIA)联合贝尔系统、调制解调器厂家及计算机终端生产厂家共同制定的用于串行通讯的标准。它的全名是"数据终端设备(DTE)和数据通讯设备(DCE)之间串行二进制数据交换接口技术标准"该标准规定采用一个25个脚的DB25连接器，对连接器的每个引脚的信号内容加以规定，还对各种信号的电平加以规定。传输距离在码元畸变小于4%的情况下，传输电缆长度应为50英尺。 　　Linux操作系统从一开始就对串行口提供了很好的支持，本文就Linux下的串行口通讯编程进行简单的介绍.
(computer serial port is a common interface, with connecting lines, simple communications, to be widely used. It is commonly used serial RS-232-C interface (also known as the EIA RS-232-C) it is in 1970 by the American Electronics Industry Association (EIA) Joint Bell System, a modem manufacturers and computer terminal manufacturers developed for serial communication standards. Its full title is "data terminal equipment (DTE) and data communications equipment (DCE) between serial binary data exchange interface technology standards," the use of a standard 25 feet to the DB25 connector, the connector pin of each signal content requirements, but also the right signal-- Ping be provided. Transmission distance in yards yuan distortion is less than 4% of the cases, the length of transm)