A PTT server includes a controlling unit, a receiving unit, a medium converting unit, and a transmitting unit. The controlling unit controls pieces of connection setting information less than the number of a plurality of PTT terminals having different specifications by complying them with the plurality of PTT terminals. The receiving unit receives a medium coded data from any one of the PTT terminals. The medium converting unit converts the medium coded data with a converting method on the basis of the connection setting information compliant with a PTT terminal for transmission destination to produce an output coded data. The transmitting unit transmits the output coded data to the PTT terminal for the transmission destination.