Key Features        
                                              
   

• Support SIP 
  
• Support Bridge and Router(NAT&NAPT) models.
  
• Support TCP/UDP/IP, ICMP, HTTP, DHCP Server .DNS client,SNTP,FTP,TFTP
• Support PPPoE static DHCP
  
• Voice Codecs: G.711,G.729A/B
  
• NAT penetration: STUN client, AVS and Citron etc.
  
• Can modify SIP register port, HTTP server port, Telnet server port and RTP port. 
  
• Support standard voice features such as numeric Caller ID Display, Call Waiting, Hold, Transfer, Do-Not-disturb, Forward,      DTMF in-band and out-of-band DTMF,
  
• Hotline (off hook autodial), ban outgoing.
  
• Support standard encryption and authentication (DIGEST using MD5, MD5- sess).
  
• Support Silence Suppression, VAD (Voice Activity Detection), CNG (Comfort Noise Generation),
  
• Line Echo Cancellation (G.168), and AGC (Automatic Gain Control).
  
• Provide easy configuration thru manual operation
  (Web interface and Telnet) or automated centralized configuration file via TFTP or HTTP.
  
• Support firmware upgrade via TFTP/FTP and HTTP.
  
• Support syslog, can send event of gateway to syslog server.
  
• Each FXS port can have one SIP account.It can be use the same SIP account for 4 FXS ports,
  but at that time,only one of the port can be used as callee,however,all port can be used as caller simultaneously.
  But when they used the different SIP account,it can be used as caller or callee anytime.