A satellite communication terminal system can execute voice communication even if it is placed at a location which is obstructed from a communication satellite by any object and has no telephone line. Further, a satellite communication terminal system for general purpose use and being extendible by using a satellite communication terminal comprises a portable satellite communication terminal for performing the voice communication with any other station through a communication satellite, a connection device and a radio telephone device including a base unit and hand units. The connection device comprises a terminal interface unit interfaced with the satellite communication terminal for controlling the transmission and reception of the satellite communication terminal and a channel control unit connected to the terminal interface unit for performing the channel connection to the radio telephone device. When the hand unit is placed at a location wherein the satellite communication terminal is not obstructed from the communication satellite, the voice communication with the other station can be accomplished through the satellite communication terminal at a location remote from the satellite communication terminal.