Design And Implementation Of Software Fax Modem Based On Blackfin

With the VoIP(Voice Over Internet Protocol) service gradually familiar to consumers, IP voice gateway, as the important part of IP phone system, already has an larger size of markets and applications. As the traditional means of transmission of still images, Fax communications, because of its legal effect, user habits and convenience, is still a basic business in PSTN. Therefore, IP voice gateway integrated fax functionality has become an urgent demand.With the project of SIPSYS Blue Dragonfly IAD-08O Voice Gateway being the research background, this paper briefly introduces the classification of fax machines and the development of fax communications, studies the basic principles of communications of G3 fax machines and the related ITU-T T.4, T.30 protocol, source coding, channel coding as well as the V series modem standards; through the study and analysis of the current status of IP fax and the project-specific requirements, puts forward the pure software solution to achieve store and forward fax functions in the SIPSYS Blue Dragonfly IAD-08O voice gateway; designs a fax modem architecture and the composition of the various functional blocks, gives a fax modem concrete realization of the C language, and for the SIPSYS Blue Dragonfly IAD-08O voice gateway hardware and software platform architecture, Fax modem software has been optimized. Finally, gives the prototype system test results. From the test results, the system performance is stable, and various performance indicators have met or exceeded target.Present SIPSYS Blue Dragonfly IAD-08O Voice Gateway has been carrying out small-volume production, and has a good results in practical application.