论文部分内容阅读
一、引言计算机通信网的建立和发展为计算机技术的广泛应用开辟了新的途径,从而使之成为现代化通信的日益重要的手段,利用公共电话交换网实现计算机远程数据传输是目前被人们普遍使用的一种方式。由于远程通信技术日趋成熟,数据通信处理设备的成本急剧下降,可靠性大为提高,所以,在用户对线路占用率不高的情况下,使用公共交换信道既兼顾了使用的有效性,又提高了整个系统的经济性。公共交换网不同于租用专线,随着传输中各次接续的路由不同,信道参数亦不相同,而且是经常随机变化的,这就要求了解并掌握使用地区和区域的线路状况,以利于系统的开发和应用。
I. INTRODUCTION The establishment and development of computer communication network has opened up new avenues for the extensive application of computer technology, making it an increasingly important means of modern communication. The use of public switched telephone network to achieve computer remote data transmission is currently widely used A way. Due to the maturity of telecommunication technology, the cost of data communication processing equipment is drastically reduced and the reliability is greatly improved. Therefore, when the subscriber occupancy rate of the line is not high, the use of the public switched channel not only takes into consideration the validity of use but also increases The whole system economy. Public switched network is different from leased line, with the transmission of the different follow-up routing, the channel parameters are not the same, but often random changes, which requires understanding and master the use of regional and regional line conditions in order to facilitate the system Development and application.