An information broadcasting method for a communication system including a plurality of stations. The communication system enables any two of the stations to communicate with one another. The communication system includes a conference trunk having at least four channels. One of the channels is an information broadcasting channel for use only in an information broadcasting operation wherein any one of the stations broadcasts information to all of the stations simultaneously via the information broadcasting channel. All other ones of the channels are conference communication channels for use in conference communication wherein any three or more of the stations communicate with one another simultaneously via any three or more of the conference communication channels. During an information broadcasting operation, any one of the stations which is receiving broadcast information from another one of the stations can transmit information to all of the stations in the system, including the station which is broadcasting information, via a vacant conference communication channel in the conference trunk, thereby engaging in bidirectional communication with the station which is broadcasting information during the information broadcasting operation.