The basic concept of communications satellites:
o Earth Station
Earth station is the radio communications station that is located on the ground and functions to communication with the space station.
The communication between the satellite earth station through space or through artificial earth satellite passive.
It is a point of communication between earth station via a satellite link, and consists of the earth to the satellite (up-link) and a link from the satellite to the earth (down link). Station earth connected to the central switching from the communications network connecting via the link terresterial.