Satellites use microwave frequencies and techniques. Satellites used for message transmission (as opposed to those, which travel around the earth on strategic and meteorological missions) remain in constant position in relation to a fixed location on earth; they are said to be in a geostationaty orbit. This position allows the satellite to of data over a long distance.
Used extensively for general telecommunications, as well as for television, satellites were originally contemplated only for long distance transworld links but are now increasingly employed for high speed; high volume transfer for example document delivery, electronic publishing. In some countries like India, satellites are used instead of underground cables because of the high cost of installing the latter.