... button, OK button, C button)Volume button(multiplex up and down keys)Hands-freeMuteHeadsetMessageMenuHoldRedialConferenceTransferVoIP ProtocolSIP 2.0Network ProtocolHTTP,BOOTP,FTP,TFTP,IEEE ... Assignment:static IP,DHCP,PPPoEDNS Client, VPN(L2TP), VLANSpeechHandle, Headset and Hands-free model availableSupport call centre by headsetsSeparated 9 Level Volume AdjustmentCall ...