... support 30 current calling lines 2)Cisco SIP 4 FXO + 4 FXS IP PBX support IAX2 1. Key features ... (RFC1350)/DNS(RFC1034,RFC1035)SIP RFC3261, RFC3262, RFC3666, RFC2543 -IP (RFC0791), TCP (RFC0793), UDP (RFC0768), ARP (RFC0826)-ICMP ... support FSK and DTMF Caller ID)2.6 Advanced IP-PBX FeaturesSupports Automatic Call Distribution- Random, Rotation, Longest ... Plug-In,Supports Web800ip pbx,voip,ip phone