The best way to test the Inmarsat-C terminal is:

The correct choice is to compose and send a brief message to your own Inmarsat-C terminal. This method allows you to directly verify that your terminal is functioning correctly by sending a message and ensuring that it is received back at your own terminal without relying on external parties or systems.

By testing your terminal in this way, you can confirm its ability to send and successfully receive messages, which is critical for operational readiness in maritime communications. It simplifies the confirmation process, avoiding potential complications that could arise when waiting for an external confirmation from a shore terminal or another vessel. This approach also eliminates variables that can affect message delivery, such as network traffic or issues with third-party terminals, making it a reliable way to test your own equipment.

In contrast, sending a message to a shore terminal or another ship introduces dependencies on those systems for verification. Relying on indicators like the “Send” light may not provide a complete picture of terminal functionality, as the light could indicate an attempt to send a message without confirming that the message was successfully received or processed.