... . 263+/H.263++ / H.2643. Audio codec: ITU-T G.711/G. 729/G.723.1A4. with PSTNvideo voip phoneStandard and Protocol Support1 ... +/H.263++ / H.264 3) Audio codec: ITU-T G.711/G. 729/G.723.1A4) Network protocols: TCP/IP, DHCP, Telnet, DNS ... ,EMS,TNT, and so on 7" Video Voip Phone,PSTN,G.711/G