Call Features 
Answer / Reject Calls
Mute / Unmute (microphone)
Call Hold / Resume
Call Waiting
Intercom
Caller ID Display
Speed Dial
Anonymous Call (Hide Caller ID)
Call Forwarding (Always/Busy/No Answer)
Blind / Attended Call Transfer
Call Parking / Pick-up
Redial/Auto-Redial
Do-Not-Disturb (per line / per phone)
Auto-Answering (per line)
3-way Conference
Hot Line

Phone Features 
4 SIP Lines
HD Voice
Handset / Hands-free / Headset mode
Phonebook (500 entries)
Remote Phonebook (XML/LDAP)
Call log (600 entries, in/out/missed)
Black/White List Call Filtering
Message Waiting Indication (MWI)
Programmable Soft keys
Network Time Synchronization
Action URL / Active URI
Industrial Standard Certifications: CE/FCC

Audio 
HD Voice Microphone/Speaker
Wideband ADC/DAC 16KHz Sampling
Codecs: G.711a/u, G.723.1, G.726-32K, G.729AB, G.722
Full-duplex Acoustic Echo Canceller (AEC)
Voice Activity Detection (VAD)
Comfort Noise Generation (CNG)
Background Noise Estimation (BNE)

Noise Reduction (NR)
Packet Loss Concealment (PLC)
Dynamic Adaptive Jitter Buffer up to 300ms
DTMF: In-band, Out-of-Band – DTMF-Relay(RFC2833) / SIP INFO

 Specification

Networking 
10/100Mbps Ethernet, dual bridged port for PC bypass
IP Configuration: Static / DHCP / PPPoE
Network Access Control: 802.1x
VPN: L2TP (Basic Unencrypted) / OpenVPN
VLAN
QoS

Protocols 
SIP2.0 over UDP/TCP/TLS
RTP/RTCP/SRTP
STUN
DHCP
PPPoE
802.1x
SNTP
FTP/TFTP
HTTP/HTTPS
TR069

RFCs 
354/1321/1350/1769/1889/1890/2131/2132/2616/2617/

2661/2833/2976/3261/3262/3263/3264/3265/3268/3311

/3489/3711/4346/4566/5630/5865

Deployment & Maintenance 
Auto-Provisioning via
FTP/TFTP/HTTP/HTTPS/DHCPOPT66/SIP PNP/TR069
Web Management Portal
Web-based Packet-dump
Configuration Export / Import
Phonebook Import/Export
Firmware Upgrade
Syslog