IP door station employing packet audio technology. Connecting the N-8640DS to an IP network (LAN/WAN) permits hands-free conversation of high sound quality to be made between N-8640DS and the intercom station connected to IP network exchange or between N-8640DS and IP multifunctional master station. Can be used in conjunction with multi-interface units through network. Equipped with single channel of control input, 5 channels of control outputs and speaker output, thereby enabling connections of external equipment such as sensor, indicator and external speaker.