Specification :

Features
Support SIP 2.0 (RFC3261) and correlative RFCs
Supprt IAX2
Codec:G.711A/u, G.7231 high/low, G.729, G.722
Echo cancellation: Support G.168, and Hands-free can support 96ms, Hand free Speaker Phone
Support Voice Gain Setting, VAD, CNG
Full duplex hands-free speakerphone
NAT transverse:support STUN client
SIP support SIP domain, SIP authentication (none, basic, MD5), DNS name of server, Peer to Peer/ IP call
SIP support 5 sip server. Can connect 5 SIP server at the same time
DTMF:Support SIP info, DTMF Relay, RFC2833
SIP application: support Call forward/transfer/holding/waiting
Call control features: Flexible dial map, Hotline, Empty calling reject, Black list for reject authenticated call, limit call, No disturb, Caller ID.
Support three way conference call
Support voice record, 240 seconds max or 3 record max, user-defined record prompt with 1 minute max
Support Phonebook 500 records
Incoming calls / Outgoing calls / Missing calls. Each support 100 records.
Support conference and voice record on SIP server
8 kind of ring type
English, Spanish, Czechoslovak alternative

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 (optional: 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

Maintenance and Management
Web ,telnet and keypad management
Management with different account right
Upgrade firmware through POST mode
Upgrade firmware through HTTP, FTP or TFTP.
Telnet remote management./ Upload/download setting file
Safe mode provide reliability
Supoort Auto Provisioning (upgrade firmware or configuration file)
Support Syslog