VoIP即基于网络的语音通信，是通信网络与计算机网络互相融合这一趋势的最直接体现。由于其节省带宽、费用低廉、体系开放灵活等特点，近年来VoIP技术得到了长足的发展与应用。与此同时，对VoIP终端设备也提出了越来越多的新业务需求，如无线接入、视频通信、多协议支持以及其他的增值业务等。而目前的VoIP终端的开发大多基于封装了协议与编码及外设接口的SOC方案或低端DSP。这种开发方案虽然简单易行，但功能有限，很难进行升级和新业务的开发。 本文的目标是设计并实现一款以通用嵌入式处理器芯片为核心的VoIP终端平台，在该平台上实现了基于IP平台的基本语音功能，同时利用通用嵌入式处理器芯片的强大运算处理能力和丰富接口，结合嵌入式软件平台为基于IP平台的多业务终端实现（语音、数据、视频）及融合预留了充足资源，只需通过接口扩展及相应软件模块开发即可实现新业务需求。 文章首先全面的分析与研究了VoIP系统中涉及到的关键技术，包括语音处理、信令协议及QoS保证技术。通过对几种主流信令协议的分析与比较，选择SIP作为本设计中采用的基本信令协议。并对SIP协议的基本功能、网络结构、协议格式及呼叫流程等进行了仔细的研究。在此基础上采用嵌入式技术完成了VoIP终端平台的设计与实现，终端以功能强大的ARM9芯片S3C2410X为核心，采用嵌入式Linux作为底层操作系统进行软件开发。具体工作包括SIP协议栈与语音编解码库在嵌入式Linux上的移植、依据Linux 2.4内核驱动规范与音频芯片手册编写的Linux音频驱动程序、并依据SIP协议栈接口规范完成了UA开发。本文详细介绍了硬件电路设计以及软件的开发过程，并根据设计目标对终端进行了通话、协议执行和功耗三个方面的测试。 文章最后分析了本设计方案相对于传统方案的优势与特点，以及采用ARM9+Linux架构对开发工作带来的影响。针对测试结果，分析了目前开发工作中的不足之处并提出了改进方案。同时提出了后续开发的计划与方案，包括UI的完善、无线局域网的支持、视频通信和多协议支持。

VoIP (i.e. Voice over IP) is the mostly direct achievement of the fusion of Telecommunication Network and Computer Network. Due to the features of saving bandwidth, low price, open and flexible structure, VoIP technology has been greatly developed and widely applied. Meanwhile, the service support requirement to VoIP terminal is also increased, such as Wireless Access, Video Communicaiton, Multi-protocol Support and other add-value services. However, the most development method of VoIP terminal is based on SOC solution which integrated protocol and codeing interface or low-level DSP chip currently. Although this method is easily to use, the function of it is limited and hard to be upgraded. If you need some new service support, you often need a brand-new solution. The target of design that presented in this paper is to realize an IP terminal platform in which general embedded prosessor is used as the core. The basic voice-call function based on IP platform is realized; at same time, the resource and interface are enoughly prepared for realization of IP Multi-service Terminal (voice, data, and video) based on the strong computing capability and abundant interface of general embedded prosessor as well as embedded software platform. The most new service requirement can be achieved by only interface extension and software development. The key technologies involved in VoIP was firstly analysed and summarized, including Voice Process, Signal Protocol and QoS insurance technology. SIP protocol was choosed as the signal protocol applied in our design based on the comparing of the maindream VoIP signal protocols. The network structure, protocol format, call process of SIP was detailedly researched. Based on these researches, the design and realization of a powerful VoIP terminal platform was achieved by using embedded technology. The terminal hardware was designed by using ARM9 embeded microprocesser as the core, embedded Linux was adopted as the software platform. The actual work I have done including the porting of SIP protocol stack, the development of Linux audio driver program according to Linux 2.4 driver specification and datasheet of audio chip, the development of UA software by using API of SIP protocol stack. The specification of chips in terminal, circuit design and development of software were all detailedly introduced in this paper. The test is performed according to design target, including voice-call test, protocol operation test and power consumption test. Finally, the advantage and features of this design is analysed by comparing to traditional solutions. The influence and benefit to development work of using ARM9+Linux architecture was also discussed. The shortage of current work is analyzed based on the testing result and the improving plan is submitted. The future work plans were provided, including GUI development, WLAN support, video communication and multi-protocol support.