中文摘要：

为了适应运营商对列车乘客信息系统越来越高的性能要求,提出了基于会话发起协议（SIP）的乘客信息系统设计的基本原则,并阐述其在列车语音通信中的应用方案.该方案充分利用SIP方法和会话描述协议谈判机制完成了会话的管理和媒体的协商.为验证方案的可行性,完成了语音控制单元的软件结构设计,并实现了各软件模块.系统测试表明,该列车语音控制单元能够准确地完成所设计的广播对讲功能.

英文摘要：

In order to adapt to the requirements and higher performance of train passenger information sys tem （PIS）, the design scheme of SIP-based PIS was proposed, in which a detailed solution for the train intercom and broadcast based on SIP was introduced. The session management and media negotiation were completed by fully using the SIP methods and SDP negotiation mechanisms. To verify the feasibility of the audio control unit, a software architecture and various software modules were implemented. The experimental result shows that the train audio control unit can accurately complete all the preset functions.