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一、引言数据通信系统是把计算机和终端设备用通信线路连接起来,以实现信息的传递、交换和处理,也即所谓“资源共享”.它是随着电子计算机的广泛应用而发展起来的一种新的通信方式,是继模拟通信、PCM数字通信后的第三大类通信方式,至今只有24年的历史(电子计算机的历史也只有38年左右). 目前,它的应用已扩展到工农业生产、交通运输、国防军事、金融贸易、科学研究以至教育、医疗、行政管
I. Introduction Data communication system is the computer and terminal equipment connected with the communication lines, in order to achieve the transfer of information, exchange and processing, also known as “resource sharing.” It is with the widespread use of electronic computers and developed a The new communication method is the third largest type of communication after analog communication and PCM digital communication, which is only 24 years old (the history of electronic computers is only 38 years or so). At present, its application has been expanded to include Agricultural production, transportation, defense and military affairs, finance and trade, scientific research and education, health care and administration