Satellite communication system and center station

A satellite communication system capable of notifying an user in speaking that a connection request is transmitted and capable of being implemented at low cost. A satellite communication system in accordance with the SCPC method using a voice activation is structured with a center station. The center station, when receiving a connection request to an user in speaking, measures a level of a carrier assigned to a reception line for the user with a demodulator. In this center station, when the level is not more than a predetermined level, the modulator transmits a signal notifying the user that the connection request is received.