Question 3-97P1

The INMARSAT-C system is primarily a low-speed data messaging system designed for reliable, non-real-time communication. **Option B is correct** because INMARSAT-C operates on a **store-and-forward** principle, meaning messages are uploaded to a satellite, stored, and then forwarded to the recipient ground station or terminal. This makes it highly suitable for both **routine data communications** like telex and email-like messages, and crucially, for **distress alerting and safety communications** within the Global Maritime Distress and Safety System (GMDSS). Its data-only nature makes it robust for these critical functions. **Option A is incorrect** because while it provides slow-speed telex-like data services, INMARSAT-C terminals **do not provide voice service**. It is a data-only system. **Option C is incorrect** because it is a store-and-forward system, not a real-time interactive system like traditional telex or voice calls, where communication is instantaneous and continuous. **Option D is incorrect** because INMARSAT-C utilizes geostationary satellites, which provide near-global coverage between approximately 70° North and 70° South latitude. They **do not provide coverage at the polar regions**, thus not offering true "world-wide" coverage.