1,2 line SIP phone 2,Support 2 SIP Aaccount 3, Support Transfer ... static IP address;15,Support voice code format: G.711A/U, G.723.1, G.729, G.726;auto-select16,User ... and Console function;19,IEEE 802.1P/802.1Q/ToS u 10 Base T/100Base TX;20,DNS;21,Transfer calls ... in a semiduplex way to ensure the talking quality; Two Line VoIP Phone