Gsm-based Wireless Fax Terminal Design Studies

With the scientific constant progress of communication, wireless technology and GSM network have got swift and violent development, Other much wireless business based on GSM network is paid more and more attention by people too, the function of the wireless facsimile is a very practical one among them. Especially for Such fields as flood fighting, news gathering, moving official working, the wireless facsimile based on GSM network will undoubtedly bring great convenience to their work, it can give maximum play to the advantage of the wireless communication, and users can really have their own" moving office ".The wireless fax is a kind of unique communication way that can receive and dispatch and write down in real time, it is also an authentic work conveys. In military field, it will play a very important role at setting up and using of our troops C~4I system, command for our troops, control, communication. The designing technique of the wireless facsimile terminal involves the communication principle, pattern process, data compress theory, technology of the coding and decoding, wireless channel, communication rules ,etc, so, the design and developing of the wireless facsimile terminal has important theory meaning and practical value.This project has carried on careful research to GSM wireless network and relevant basic theories of facsimile communication, on this basis, has designed and developed three kinds of terminals of wireless facsimile based on GSM network. The design of every kind of terminal is combined together by two parts, the hardware design and the software design.First, design and develop a GSM wireless facsimile terminal based on ISA bus. Through the study on ISA bus and wireless MODEM of GSM, has designed the put-inside hardware card of the computer, to study the channel characteristic of GSM network, the focal point of software is to design the wireless fax communication rules which accord with GSM network. This is one of the difficult point questions in the design. The finished facsimile terminal can complete voice communication with any telephone subscriber, and send short messages with the mobile subscriber each other, it can aslo send the facsimile file of the single page to an ordinary G3 fax-machine in PSTN network.Second, design and finish a GSM terminal of wireless facsimile based on USB interface. This is the most outstanding research in this project . Through the study on USB interface andUSB interface chip , has designed a portable plug-and-play facsimile terminal hardware platform based on USB interface. The design of the interface of the hardware has emergent novelty. Software design not merely has finished the realization of the wireless fax communication rules, but also designed the control of the scanner , the control of the lens , the colored facsimile image catching , two value treatment of colored image , the fax data of the two value treatment result compressing and MH coding . Those software designs are the focal points in this project. The finished facsimile terminal can complete voice communication with any telephone subscriber , and send short messages with the mobile subscriber each other, it can also catch image from the scanner or the lens then carry on two value treatment and MH coding then send the file to an ordinary G3 fax-machine in PSTN network.Third , design and research a platform of wireless facsimile based on MCS-51 microcontroller. Consider for expand outside scan , writing down device etc , the interface reserving outside and expanding specially at the time of this terminal hardware design . And has designed the platform of the main control part taking MCS-51 as the core chip, and has designed the wireless MODEM interface and peripheral logic. The software has carried on the transplantation and debugging of the code on the rules of wireless communication. The finished facsimil terminal can complete voice communication with any telephone subscriber , and aslo send the fax file of the facsimile file stored in outside RAM to a G3 fax-machine in PSTN network.