Study On The Technology Of DTMF Communications And Its Applications

During these years, athough the rapid develop of the broad band communications is continue, the narrowband communications are still the main means for the peoples' communication. The narrowband communications are those communication networks that remain low speed. It is an important significance for our country to develop the cheap and practical technique of narrowband communications. The development of narrowband communications can rapidly raise the whole standards for communications and bring out lots of practical values in our country.According to the situation of narrowband communications, the article put great emphasis to study the principles and key technologies of the communication base on DTMF.1) The excellences and the shortages of the DTMF communication are researched in the article.2) According to the market requiring, the KT calling systems are reconstructed.3) The separating technology between power and the signal is presented in this article. The hard problem which cause the mutual interference from the DTMF signal and the voice signal while they are both transmitted on a same twisted-pair is resolved in this article4) The KT calling system's software is also presented in this article and the system is applied in some hospitalsThe excellences of the system with the technology are list below.①The data can be transmitted far distance. It can transmit thousands kilometer far away. The frequency of the signal is less than 2K Hz and it consume less power.②The signal remain low frequency and low power consuming, The capability of anti-jamming is excellent.③It is esay to extend the other functions, such as transmitting the data of pulse. It can be developed to long-distance controlling and colligate management.According to the technologies and principle of DTMF communications present-ed above and the most extensive adopted chips, the article have improved the s-ystem of the DTMF communications base on microprocessor. The system have achieved perfect performance while its cost is still remain low standard and have good praise in the hospital which have used our system.