The state-of-the-art Enterprise IP Phone, is designed for corporation and business user, and make your business call to be more easy and flexible. Supports 5 SIP lines and POE. Outstanding business application functions such as Pre-dailing, call transfer between different SIP Lines, DND, Message (Voice and Text), N' Pad, etc. Voice Features Support 5 line SIP accounts Support SIP 2.0 (RFC3261) and correlative RFCs Codec: G. 711A/u, G. 7231 high/low, G. 729a/b Echo cancellation: Support G. 168, and Hands-free can support 96ms, Hand free Speaker Phone Full duplex hands-free speakerphone Support Voice Gain Setting, VAD, CNG NAT transverse? Osupport STUN client SIP support SIP domain, SIP authentication (DNS name of server, Peer to Peer/IP call SIP support Pubic & Private server. Can connect to Public SIP and Private SIP server at the same time DTMF? OSupport SIP info, DTMF Relay, RFC2833 SIP application: Support Call forward/transfer/holding/waiting Call control features: Flexible dial map, support Hotline, Empty calling No. Reject service, Black list for reject authenticated call, No disturb, Caller ID. Support conference call and voice record Support Phonebook 500 records Incoming calls / Outgoing calls / Missing calls. Each support 100 records. 9 kind of ring type and 2 user-defined music rings Support conference and voice record on SIP server Support voice record, 20 minutes total, 5 minutes max of 4 records or 15 records max Support IAX2 Network Features WAN/LAN: Support Bridge and Router model Support basic NAT and NAPT Support PPPoE for xDSL Support DHCP Client on WAN Support DHCP Server on LAN Support VLAN (voice vlan/data vlan) QoS with DiffServ Support DMZ Support VPN (L2TP/UDP TUNNEL) Support DNS Relay, SNTP Client, Firewall Network tools in telnet server: Including ping, trace route, telnet client Special Features Support headset 5 programmable key, realizing memory keys or SIP line keys Support N'Pad record Support desk position and wall-mountable LED indicator to show missed call or voicemail