VSAT (Very Small Aperture Terminal) is a two-way satellite ground station with a dish antenna that is smaller than 3 meters. Can possible to transmit Data rates range from 56 Kbit/s up to 4 Mbit/s. VSATs are most commonly used to transmit narrowband data (point of sale transactions such as credit card, polling or RFID data; or SCADA), or broadband data (for the provision of Satellite Internet access to remote locations, VoIP or video). VSATs are also used for transportable, on-the-move (utilizing phased array antennas) And in VSAT Communications data passes through a satellite using a signal path known as a transponder. satellites have between 24 and 72 transponders. A single transponder is capable of handling up to 155 million bits of information per second. With this immense capacity communication satellites are an ideal medium for transmitting and receiving almost any kind of content - from simple voice or data to the most complex and bandwidth-intensive video, audio and Internet most common VSAT configuration is the TDM/TDMA star network. This have a high bit rate outbound carrier (TDM) from the hub to the remote earth stations, and one or more low or medium bit rate Time Division Multiple Access (TDMA) inbound carriers.


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http://en.wikipediawiki/Very_small_aperture_terminal
http://mediaschool.ohiou.edu/its/briefs_vsat.html
http://macrosatVSAT-Technology.html