| With the surge appearance of high buildings, elevator as the necessary vertical transportation tool and even the special equipment in terms of people's live is more and more widely used. How to ensure safety and efficiency of elevator operation is focused by the society.The national stardard safty regulation of elevator production and installation GB7588-2003 provides that emergency alarm device must be equipped within elevator car to enable passengers appeal for help. The device should adopt a voice intercom system to maintain connection with the rescue service.Up to now, all elevator suppliers adopt such a system that based on analog signal. But it is easily interfered by elevator electrical power device to such a degree that the voice hardly be heard. So the development of elevator voice intercom system is that analog transmission method will be substitute by digital method.This paper introduces the character, evolution history, the R&D and application status and trend of elevator voice intercom system. It also analyzes the constitution, the function and the work style of the system. It proposes the solution of the elevator digital voice intercom system, and developed a prototype successfully. This prototype realizes good voice quality, easy operation, and anti-interferance performance, which reaches the design goal.In the hardware design section,this paper discusses the power supply circuit, the voice codec circuit, the MCU circuit, the interface circuit of every intercom device and hardware reliability design. In the software design section,this paper discusses the thought of delaminated and modularized designing for the software as well as its advantage, introduce the whole flow of the software, and its reliability design. I have accomplished the mission of developing functional prototype. At the end of the paper, I summarized the research and develop work, propose some problems, which must be solved afterwards, and fix direction for the following R&D.
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