Research On Campus Telephone System Based On Asterisk

In recent years, with the development of open and distance education for our colleges and universities, computer technology gradually penetrated into the campus network. The broadband multimedia including voice and video, and network classroom have brought great convenience for teachers and students. But most of the telephone systems in the universities of China are the telecommunication phone network without additional basic phone support systems. At the same time, it is required a new technology such as Asterisk to alleviate the disadvantages of higher communication fee and low communication efficiency in the current campus telephone system as soon as possible.In this paper, according to the actual situation of the campus network in Dalian Vocational Technical College, we developed an efficient Asterisk-based telephone system through the existing network equipment in the campus. The system is based on the use of VoIP technology to transfer voice, which can build a successful IP telephony network within the campus, and provide a high-efficiency and low cost communication platform to effectively improve communication between teachers and students in different school districts. It is helpful to save the cost of internal communications, while also improving the efficiency of work and study.This paper firstly described the basic principles of VoIP and several key technologies, mainly focusing on four major analysis of the VoIP signaling protocol, also introduced the voice codec, squelch suppression and comfort noise generation, echo cancellation, jitter processing, packet loss compensation and other key technologies. And then, a comprehensive study of the Asterisk software system has been introduced, including its architecture, dial plan, install, configure, as well as some practical examples and tests. On this basis, an in-depth analysis of the campus network and the status of the telephone network in Dalian Vocational and Technical College have been given. According to the main problems and requirements, we designed a campus network based on Asterisk VoIP phone system, and described its involved hardware equipment and software and the workflow, design number and dial plan, and analyzed the interoperability with the PSTN. Finally, the system has been tested, including functional test, compatibility test and performance test. According to the test results, from three aspects of the campus telephone system in the actual operation, i.e., voice quality optimization, security and management, some of the key issues have been also discussed in this paper.