... 1.Support PSTN and VoIP 2.Public phone directory 3.Private phone directory 4.Clear Voice Dual-module IP PHONE 1.Technical ... ,Headset,Message,MenuDirectory,Service,Hold,Redial, Conference, TransferVoIP protocol SIP 2.0Network ProtocolHTTP , BOOTP , FTP , TFTP , IEEE 802.1Q , *IEEE 802 ...