IAD04(W:4S) 4 port VOIP gateway include 4 FXS ports gateway,and with 1 ... T LAN ports;1 RS232 port;VoIP protocol: H323 v2,H323 v4,SIP,compliance ITEF RFC3261 standard network protocol: IP,TCP,RTP ... JITTER BUFFE Security l Embedded firewall module, packet filter, IP port shielding, anti URL attack Support signaling, media, fax encryption, ... : 5-95% non-condensing l EMS index:<10db 4 port VOIP gateway