Inmarsat

Vast areas of the world are still beyond the reach of fixed and cellular
telecommunication networks. These areas are either sparsely populated or
too economically depressed to support conventional communications
infrastructure. Inmarsat has been operating a global satellite system since
1982. Through a system of four satellites, Inmarsat provides a worldwide
range of high quality telecommunications services that are easy to setup
and operate and for a fraction of the cost of conventional systems.

Access to the system is provided through satellite communication terminals
like the mobilfone, Compact-M, or Worldphone. When a call is made, the
terminal directs a signal to one of the four satellites which in turn
redirects the signal back to an Inmarsat receiving station on earth called
a Land Earth Station (LES). The signal is then routed through the Public
Switched Telephone Network to complete the call.

To reach another Inmarsat terminal, the LES would redirect the signal back
to one of the four satellites corresponding to the other terminal's
location which in turn redirects it down to the other terminal to complete
the call. The same basic process is used to transmit fax and data
information as well.

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