基于N-ISDN的数字用户终端通信系统的研究与设计

【作者】 唐浩；

【导师】 刘国锦；

【作者基本信息】 南京师范大学 ， 电路与系统， 2007， 硕士

【摘要】 近年来，随着经济的快速发展，用户对于数据通信业务的需求剧增，大量的小型数字程控交换机产品广泛用于机关、企业和工矿等内部通信量大的社会集团。该类交换机一般具有自动交换、汇接、会议和调度等功能。既能够实现内部呼叫也能接入市话交换网。大多数的设备只支持模拟用户接口，用户和交换机之间的用户线上传输的是模拟信号，速率比较低且衰减大易受干扰。由它组成的专用通信网络以支持语音通信业务为主，业务简单同时功能单一。因此为了克服其在接入网方面的弱点，满足专用网用户越来越高的需求，许多该类交换设备需要进行升级改造。本文中的交换机正属于这类设备。ISDN用户-网络接口技术是一种先进的用户接口数字化技术，本文正是选择了ISDN(综合业务数字网)作为研制的参考模型。在本校研制的程控交换机的基础上加装数字用户接口板，以实现用户接口的数字化。本文阐述了ISDN用户-网络接口的基本理论和相关协议。详细分析了数字用户接口板的硬件设计和软件开发方案。本文遵循软硬件相结合的原则，选用了Motorola的MC145572芯片实现N-ISDN在U节点上的物理接入。实现用户线上的全双工数字通信，2B+D的数据传输速率达到144kbit／s。采用PTTA8952P芯片部分实现数字链路层的协议功能。同时选用CPLD(复杂可编程逻辑器件)完成了板上大多数的逻辑实现工作。确保了系统快速、高效、可靠的运行。升级后的交换机可提供语音、数据、图像等多种业务，能满足用户日益增长的业务需求。同时本文的改造方案具有通用性，对交换机的原有结构基本未做改动，因此很容易就可应用到许多型号的同类设备上去。更多还原

【Abstract】 In recent years,along with the fast development of economy,the users’ demands of data communication is increasing fast,a large number of small scaled digital program-controlled exchange device are widely used by many organizations,corporations and mineral enterprises...ect. The type of these device generally offer the function of auto-exchange,connection,conference and coordinate.They can realize the inner call and can also connect into the public exchange network.Most of them only provide the traditional analog interface to users,analog signal is transmited across the line between the user and the exchange,the rate is lower and is easy to be interfered. So the mainly function offered by the private telecommunication network built up with them is limited only in voice service fields.The Service is simple and the function is simplex.Therefore for overcoming the weakness of network connecting,and satisfy the increasing demands of users in the private telecommunication network,many of these exchange device should be reformed or upgraded.The exchange in this thesis belongs to this type.ISDN(Intergrated Services Digital Network)User-Network technique is a kind of advanced technique of user interface numerical. So this paper chooses ISDN exchange as reference model and gives the full resolution.We add the digital user interface board to the program-controlled exchange developed by our own school to realize the numerical of the user interface.This paper expound the basic theories and related protocol of ISND User-Network interface and analyze the project of designing the hardware and software of the digital user interface board.This paper follows the principle which combines hardware and software.choose MC145572 which produced by Motorola to carry out the physical connection on the U node of N-ISDN.Realize the whole ambilateral communication on the user line and the 2B+D data rate reaches to 144kbit/s.Adopt PT7A8952P to carry out part of the protocol on data link level. Most of the logic work are carry out by CPLD(Complex Programmable Logic Device) on the board to insure the fastly,efficiently and dependable of the system,After getting reformed,the exchange can offer voice,data,image transmission services.It can satisfy the increasing user demands.Meanwhile the resolution discussed by this paper keeps the old exchange framework at the most benefits and can be applied to other model small scaled digital program-controlled exchange easily.更多还原