What is the primary function of a LES?

The primary function of a Land Earth Station (LES) is to provide direct communications between the Inmarsat station placing a call and the station receiving the call. This role is crucial in facilitating the connection and ensuring that voice and data communications can take place effectively between maritime vessels and terrestrial networks.

Specifically, the LES acts as a bridge in satellite communication systems. It receives signals from the maritime users aiming to initiate calls and then relays those communications to the appropriate receiving stations. This function is essential because it allows users onboard ships to connect directly with shore-based networks or other vessels, thereby enhancing communication capabilities across vast distances.

The other options focus on related functions but do not precisely describe the core responsibility of a LES. Monitoring and controlling communications, while part of the operational duties of a LES, do not encapsulate its primary role as a communication link, which is why this answer stands out. Similarly, multi-mode communications and determining the best satellite for the connection, while relevant to telecommunications, are secondary considerations that do not define the fundamental purpose of a LES.