NXD-804 is a commercial SIP VOIP telephone developed by ESTONE Company himself. It is a luxe SIP VOIP telephone compatible with SIP V2, achieving full duplex hands-free call and having 128*64 graphics LCD with back light, which can display many languages. When it is disposed into H.323, NXD-804 cancooperate with Gateway and GW of most H.323. It also has perfect H.450 protocol to complete all telecom value-added services such as call transfer, call forward, call waiting, etc.. Cooperating with soft exchange system, it can totally replace traditional PBX or KEY LINE PHONE. It can also be used as LAN phone or hot-line phone. When it is disposed into SIP, NXD-804 can cooperate with most SIP system. Besides having popular g.723 and g.729, it can use low-priced GSM voice compression algorithms. This model is the first-selected one for telecom operators and the main type exported by Estone Company；