Network Gateway With Sip Support

* Support SIP
* Support Bridge and Router (NAT&NAPT) models.
* TCP/UDP/IP, ICMP, HTTP, DHCP Client (WAN Interface), DHCP Server(LAN Interface), DNS Client, DNS Relay, SNTP, PPPoE, FTP, TFTP.
* Voice Codes: G.711(A-law/U-law), G.723.1, 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, 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.