串口通信的概念非常简单，串口按位（bit）发送和接收字节。尽管比按字节（byte）的并行通信慢，但是串口可以在使用一根线发送数据的同时用另一根线接收数据。它很简单并且能够实现远距离通信。比如IEEE488定义并行通行状态时，规定设备线总常不得超过20米，并且任意两个设备间的长度不得超过2米；而对于串口而言，长度可达1200米。典型地，串口用于ASCII码字符的传输。通信使用3根线完成：（1）地线，（2）发送，（3）接收。由于串口通信是异步的，端口能够在一根线上发送数据同时在另一根线上接收数据。其他线用于握手，但是不是必须的。串口通信最重要的参数是波特率、数据位、停止位和奇偶校验。-The concept of serial communication is very simple, serial by bit (bit) to send and receive bytes. Although more than by byte (byte) of parallel communication slow, but can use a serial line to send data at the same time another line to receive data. It is very simple and can achieve long-distance communications. For example, the definition of IEEE488 parallel access mode, the total line often provides equipment shall not be more than 20 meters, and between any two devices may not be more than two meters in length　and in terms of the serial port, up to 1200 meters in length. Typically, serial code for the ASCII character transmission. 3 lines of communication to use to complete: (1) ground, (2) send, (3) to receive. Due to the asynchronous serial communication port to send data in a line at the same time another line to receive data. Other lines for the handshake, but not necessary. Serial communication the most important parameter is the baud rate, data bits, stop bits and parity.