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随着计算机通信技术的发展和普及,利用专用通信线路组成的计算机网络,由于国内线路资源紧张、费用高等原因,已经不能满足日益增长的用户需求,利用现有的市话网络担负电话和计算机通信业务,已成为一个新的发展趋势。但是,由于目前我国市话线路误码率较高,通信质量较差,已投入使用的一些应用系统在市话网繁忙的高峰时期,往往由于严重的干扰而不能进行正常的通信。为解决这一问题现介绍一种采用041C单板机和电话裁决控制电路做成的专用通信控制器。该系统选用X25建议中LAPB规程作为链路层协议。经各种复杂通信环境测试和使用,获得了满意的通信效果,本文着重介绍LAPB规程实现中提高系统可靠性的措施。
With the development and popularization of computer communication technology, the computer networks which use dedicated communication lines can not meet the increasing demands of users due to the shortage of domestic line resources and the high cost, and they use the existing local telephone networks to undertake telephone and computer communication services , Has become a new trend of development. However, due to the current high bit error rate of local lines in our country and poor communication quality, some application systems that have been put into operation often can not perform normal communication due to serious interference at the busy peak of the local telephone network. To solve this problem is to introduce a 041C single board machine and telephone ruling control circuit made of a dedicated communications controller. The system uses the LAPB protocol recommended by the X25 as the link layer protocol. Through a variety of complex communication environment testing and use, access to satisfactory communication results, this article focuses on the introduction of LAPB procedures to improve system reliability measures.