A telephone, when dialing another telephone, gives first address information of another telephone to a server, and obtains call identifying information corresponding to the first address information and second address information as a dial number of a control unit from the server. The telephone gives the control unit a call containing the call identifying information based on the second address information. The control unit obtains the first address information corresponding to the call identifying information from the server, and allows the call from the telephone to arrive at another telephone corresponding to the first address information.