The price as low as USD 38.99 Voice Functions and Features

Protocols: SIP RFC3261,RFC 2543, IAX2, H.323
Codecs: G.711A/u, G.7231 high/low, G.729
Echo cancellation: Supports G.168
Powerful digital signal processing (DSP)
NAT transversal: supports STUN client, Citron, AVS
Voice activity detection (VAD) and comfort noise generation (CNG)
Advanced adaptive jitter control and packet loss concealment
Supports SIP info, DTMF Relay, RFC2833

Calling Functions and Features

Hands-free can support up to 96ms
Call forward/transfer/holding/waiting
Flexible dialing map
Caller ID identification
Support hotline
Empty calling no. reject service
Black list for rejected authenticated call
Do not disturb
Supports conference and voice recording

Network Functions and Features

WAN/LAN: Supports bridge and router model
PPPoE for xDSL, DHCP Client on WAN
SNTP Client, 802.1p/q, Diffserv
Network tools in telnet server include ping, trace route, telnet client

Maintenance and Management

Supports boot monitor
Can upgrade firmware through boot monitor
Can upgrade firmware and configuration file through HTTP, FTP and TFTP
Can config through web, keypad, telnet
Supports syslog