FACSIMILE TRANSMISSION OVER DIGITAL SATELLITE LAND-MOBILE CHANNELS

The importance of facsimile communication over public telephone networks is evidenced by the rapid growth in the number of Group 3 facsimile terminals. In this paper, the main characteristics of a real-time approach are described whereby facsimile signals are demodulated and their associated protocols are packetized and converted by a Facsimile Interface Unit (FIU) to a format suitable for transmission over digital land-mobile satellite channels. The FIU concept was developed to allow off-the-shelf facsimile terminals to be interconnected via the PSTN through satellite networks and to permit the provision of enhanced user services, such as facsimile broadcasting (point-to-multipoint) to mobile terminals, to be offered. In addition, the FIU concept is designed to mitigate for the longer access and transport link delays encountered in mobile satellite systems.