Network Protocol
SIP v1 (RFC2543), v2(RFC3261)  IP/TCP/UDP/RTP/RTCP
IP/ICMP/ARP/RARP/SNTP          TFTP Client/DHCP Client/ PPPoE Client
Telnet/HTTP Server             DNS Client  NAT/DHCP Server

Codec
G. 711: 64k bit/s (PCM)  
G. 723. 1: 6.3k / 5.3k bit/s
G. 726: 16k / 24k / 32k / 40k bit/s (ADPCM)
G. 729A: 8k bit/s (CS-ACELP)
G. 729B: Adds VAD & CNG to G. 729

Voice Quality
VAD: Voice activity detection  
CNG: Comfortable noise generator
LEC: Line echo canceller  
Packet Loss Compensation  
Adaptive Jitter Buffer

Call Function
Call Hold  
Call Waiting  
Call Forward  
Caller ID  
3-way conference

DTMF Function
Tone
Ring Tone Ring Back Tone  
Dial Tone  
Busy Tone  
Programming Tone

Phone Function
Volume Adjustment  Speed dial key  
Phone book  
Flash

IP Assignment
Static IP  
DHCP  
PPoE

Security
HTTP 1.1 basic/digest authentication for Web setup
MD5 for SIP authentication (RFC2069/ RFC 2617)

QoS
ToS field
NAT Traversal
STUN
Configuration
Web Browser  
Console/Telnet  
IVR/Keypad

Electric Spec:
Voltage: 12V DC
Power adapter: DC 12V/500mA
Network interface: 1 RJ-45 Ethernet connectors

Tel interface: 2
Model:
Model    Print    UI       FXS  Life Line  RJ45
GW200CN  English  Chinese  2    0          1
GW200EN  English  English  2    0          1