Design And Implementation Of The Digital Fax Used In Double Networks

Nowadays, the means to transmit the information with the traditional fax is to change the scanned images or graphs into the data transmitted through telephone networks by translating the date and analogue signals with the modulation and demodulation (MODEM). Traditional faxes today could not meet more and more various demands of the different users due to two main reasons. The first is the limitations from the expensive telephone bills, the low transmission rates and reliability on the telephone; The second is that the paperless facsimile , storage and processing of fax file with a computer are being used more and more widely, making the great impact on the traditional fax with the popularity of Internets.With the popularity of the Internet, this dissertation is to mainly study a special fax that can be used in both Internet and ordinary telephone networks. The outstanding differences between such a digital fax used in double networks and an ordinary fax are as follows: adding a network interface, having two transmission models in Internet and the ordinary telephone networks, enhancing its function, expanding its application suitability, increasing the transmission rate and reliability, guaranteeing good quality of the images, and greatly reducing the bills of long-distance telecommunications by the fax.Based on a discussion of the basic theory of the fax telecommunication and the development of the embedded system software, this dissertation has proposed the general scheme of the digital fax used in double networks, performed its design of software and hardware modules, implemented the modules of software and hardware, and debugging for two microcomputers communicating each other. The efforts made in this dissertation have laid a concrete foundation for the development of such a digital fax used in double networks.