Which mode of communication is possible through an Inmarsat-C SES?

Inmarsat-C satellite communication systems provide several features primarily designed for data transmission, including the ability to send and receive TELEX messages and e-mails. This mode of communication leverages the satellite network to facilitate reliable transmission of messages, especially in maritime contexts where traditional communication methods may be impractical due to distance or environmental factors.

TELEX operates over the Inmarsat-C system by converting text messages into a format suitable for satellite transmission, allowing users to engage in written communication asynchronously. This capability is especially valuable for vessels that need to maintain contact with shore facilities or other ships while at sea, ensuring that critical operational information can be communicated effectively.

While other options like SITOR (NBDP), radiotelephone, and DSC are important communication methods in maritime safety and operational contexts, they do not directly utilize the Inmarsat-C SES for transmission. SITOR and NBDP are designed for specific types of data transmissions but do not operate over the Inmarsat-C system. Radiotelephone is primarily for voice communications, while DSC focuses on distress signaling and does not involve general data transmission capabilities like email and TELEX provided by Inmarsat-C. Thus, the correct choice highlights the unique data capabilities of the Inmarsat-C SES.