... Billing Interface, Second Stage Dialing and Ring-back Tone, DTMF Auto Dial, Tone Detection, RTP voice Proxy (for NAT traversal), T ... , INFO (SIP) , In-BandHardware· Ethernet Interface ConnectorRJ-45, 10/100 Base-T, 10/100 Auto Sensing·E1/T1 interfaceRJ-45· System Memory128 MB ...