| Recently, the communication technology has advanced rapidly in our country. The telephone network based on circuit-switch and digital program controlled exchange technology plays an important role in the whole communication network. As following the coming of information age, people enjoy the pleasure of the information society, at the same time, also has encountered many new challenges. It is very necessary to learn and master program controlled exchange technology for engineers and college students.This paper is based on a lot of literatures and relative design schemes. According to the principle of program controlled switch, an experimental system based on ARM has been designed mainly for the library of high school and other related institute. The union of ARM and CPLD is the main controller system, and the other model is designed for different function division. Most part of basic experiment can be completed using this system, more over, some program debug experiment related with program switch also can be realized.This system is made up of two parts, hardware and software. The hardware includes CPU control part, subscriber line interface circuit, exchange network, trunk interface circuit, signal tone circuit, DTMF circuit, color ring back tone circuit, LCD display circuit and so on. The software also is made up of two parts, basic program and cycle program. At last, the uC/GUI program on the LCD display has been introduced. Many kinds of experiment can be accomplished, such as the artificial exchange, space division exchange, time division exchange, digital repeat, and coloring ring back tone.This system has been used in practice now. Compared with other experimental systems of program-switch, much more expansion interfaces have been provided. The customer can expand these interfaces by themselves. At the same time, the system also has other advantage, such as the good interface between the system and operator and easy operation. |
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