English Homework2

Could you explain this graphic?

Satellite Internet works from the use of geostationary satellites in orbit around the Earth. This diagram shows a satellite relay for communicating two networks. One of them is located on Los Angeles-North America and the other is crossing the Pacific Ocean, in Barcelona-Spain.
Both are formed by a laptop PC, a Central PC and a PDA. The first uses a wireless conection an phone lines to transmmit the dataand the other one uses a modem to do it and works with fibre optic cables.
How do they work? You can write us about your opinion!!!