... at the same time 2.Provide two backup SIP servers IP Phone system: CPH-665 Features:Support three SIP servers running ... ) Support Voice Gain Setting GSM, AMR, ILBC Support bridge and routing modeDTMF Sip Info, DTMF Relay, RFC2833Support PPPoE, (used ... tools: ping, trace route, telnet clientWeb administration, telnet configuration and keypad operationSupport HTTP, FTP, TFTP software upgrade or configure. ...