What is the correctly formatted Inmarsat-C address book entry for a fax machine on an F77 terminal in the IOR?

The correct Inmarsat-C address book entry for a fax machine on an F77 terminal in the IOR region follows a specific formatting standard. Inmarsat-C addresses for maritime communication consist of a 15-digit number, where the first part indicates the country code and the next part typically designates the service type, followed by the individual terminal number.

The entry 870763240864 adheres to this format. The prefix 870 indicates that it is an Inmarsat terminal number, and the sequence that follows is properly structured as a unique identifier for the particular fax machine. The use of the appropriate prefix, combined with a correct total length of digits, confirms its validity as a contact point for sending and receiving faxes within the Inmarsat communication system.

In contrast, the other entries either do not comply with the established conventions for Inmarsat-C addresses, or they might use inappropriate prefixes or incorrect digit counts, leading them to be invalid for establishing communication through Inmarsat services. Thus, it is essential to identify the correctly formatted entry to ensure successful connection and communication within the maritime environment.