Which sequence is valid for requesting an automatically dialed ship-ship call to an F77 terminal on a vessel tracking the IOR satellite?

To request an automatically dialed ship-to-ship call to an F77 terminal using the Inmarsat system, you need to follow a specific dialing protocol that includes the country code and the other relevant information.

The correct answer involves using the appropriate prefixes that align with the Inmarsat F77 structure. Inmarsat F77 utilizes specific country codes and certain patterns that must be adhered to for successful connections. The choice identified reflects a valid sequence that corresponds to an established procedure for making such calls.

When looking at the structure of this valid sequence, "0087" is the correct international dialing code for accessing satellite services in the Inmarsat network. The subsequent digits in the sequence represent the specific terminal identifier for the intended vessel. This is quite crucial, as the correct sequence ensures that communication reaches the desired terminal.

Other options have either incorrect prefixes or codes that do not correspond to valid Inmarsat calling procedures or incorrectly formatted numbers, making them invalid for establishing a connection to an F77 terminal. This underscores the importance of knowing the correct dialing conventions for maritime communications, particularly under the GMDSS framework, ensuring that vessels can communicate effectively and safely on the open waters.