This chapter aims at providing the framework of VSAT technology in the evolving contextof satellite communications in terms of network configuration, services, operational and regulatory aspects. It also can be considered by the reader asa guide to the following chapters which aimat providing more details on the most important issues. VSAT NETWORK DEFINITION VSAT, now a well established acronym for Very Small Aperture Terminal, was initially a trade mark for a small earth station marketed in the 80s by Telcom General in the USA | VSAT Networks Copyright 1995 John Wiley Sons Ltd ISBNs 0-471-95302-4 Hardback 0-470-84188-5 Electronic 1 INTRODUCTION This chapter aims at providing the framework of VSAT technology in the evolving context of satellite communications in terms of network configuration services operational and regulatory aspects. It also can be considered by the reader as a guide to the following chapters which aim at providing more details on the most important issues. VSAT NETWORK DEFINITION VSAT now a well established acronym for Very Small Aperture Terminal was initially a trade mark for a small earth station marketed in the 80s by Telcom General in the USA. Its success as a generic name probably comes from the appealing association of its first letter V which establishes a victorious context or may be perceived as a friendly sign of participation and SAT which definitely establishes a connection with satellite communications. In this book the use of the word terminal which appears in the clarification of the acronym will be replaced by earth station or station for short which is the more common designation in the field of satellite communications for the equipment assembly allowing reception from or transmission to a satellite. The word terminal will be used to designate the end user equipment telephone set facsimile machine television set computer etc. which generates or accepts the traffic that is conveyed within VSAT networks. This complies with regulatory texts such as those of the International Telecommunications Union ITU where for instance equipment generating data traffic such as computers is named Data Terminal Equipment DTE . VSATs are one of the intermediate steps of the general trend in earth station size reduction that has been observed in satellite communications since the launch of the first communication satellites in the mid 60s. Indeed earth stations have evolved from the large INTELSAT Standard A earth stations equipped with antennas 30 m wide to .
