Data services in the Inmarsat communication system

Quite a number of data services are available in the Inmarsat communications system, from low-speed store and forward up to full duplex high speed 64 or 56 Kbit/s real-time data services. The data services are available from practically anywhere and do not require any infrastructure except power supply for the Inmarsat terminal which can be a car battery or solar panels and a direct line of vision to one of the satellites. The integrity of the information which goes through the system is achieved by using forward error correction (FEC) procedures. In medium-speed data services ARQ/V.42 procedures are available in addition to FEC. Data services are the basis for implementation of different widely used applications, though in quite a number of cases when using specific solutions built taking into account the specific features of the Inmarsat channels the effectiveness of the utilisation of resources can be higher. The connection of a computer to a new digital satellite terminal is effected directly as to a modem and there is no need to use any modems anymore. Basic and extended (to control specific parameters) sets of AT commands are available.