To implement a key telephone system through an IP (Internet protocol) network, if real-time broadcast information is transmitted by multicast communications, restriction to prevent a rapid increase in network traffic is received, an additional special protocol is required, and it is hard to ensure the confidentiality of information. If real-time broadcast information is transmitted by unicast communications, transmission processing is centralized on a broadcast information transmission apparatus, the traffic becomes enormous, and a broad communication band and a high processing capability become necessary. Therefore, a transmission dedicated apparatus is provided between a broadcast information transmission apparatus and a terminal for distributing the transmission function and traffic. The broadcast information transmission apparatus needs only to manage the transmission dedicated apparatus. A plurality of terminals, etc., can be connected to the transmission dedicated apparatus. Further, a transmission dedicated apparatus can also be connected as a subordinate node to the transmission dedicated apparatus.