The Study Of The Large-scale Telephone Line Expander

With the advancement of people's life and the development of socialist market economy, people require so many telephones that the capacities of the telephone lines which had been put originally couldn't reach to the users' satisfaction. Therefore, searching a modern communication technique to communicate for more users by using the limited channels resources in communication fields is becoming the main subject of researching.Adopting the technique of the multi-channel share which has already been widely used in communication fields such as satellite communication and mobile communication is an effective method to increase the capacities of communication system and the utilization factor of the channels. Multi-channels share means that all the channels (n) of the communication system are occupied to communicate by all the users (m). In this article, with the principle of the multi-channels share, the large-scale telephone line expander which can be used not only for more people (16-32) to reach the aim of the telephone line expansion with a few telephone lines (4-6), but also for every telephone to communicate with any idle telephone line is researched to increase the utilization factor of the channels.On the basis of confirming the plan of the whole design, the technique of modern digital communication, computer and electronic technique are supplied to design the hardware of the large-scale telephone line expander and program the software, also the debugged and the tested experiment are done. In order to secure the reliability of communication and the stability of work, the measures of anti-jamming the disturbance are stepped from the aspects of both hardware and software. The expander is a real-time communication system, so the signal was transmitted by the way of which is formed into through both the channel associated signaling transmission mode and the common channel signaling transmission mode. As a result, the reliable connection is ensured for the communication channels.In this article, Based on the knowledge of stochastic process and combined with the software MATLAB, the configuration of shared lines for the limited users system is simulated and analyzed, and the relationship among the call congestion (B) ,the shared !ines(n),the users(m), the traffic(A) and the utilization factor of telephone lines is confirmed . According to the principle, the method of optional configuration of the shared lines is proposed.The large-scale telephone expander can be used for more users( 16-32) to expand capacitor with a few telephone lines(4~6) based on the principle of multi-channel share and dynamic channel distributed mode. And it is helpful to increase the utilization factor of the channels and decrease the project cost of investment. In other way, the telephone line expander which has many characteristics just as the little of declination, the far distance of communication, the convenience of using and protecting can transmit tone signal directly and is suitable for the performance of telephone line. So the telephone line expander has a future prospect and using value.