... SIP 2.0 (RFC3261) and correlative RFCs Codec:G.711 A/U Law, G.723.1, G.729a/b, ... support 96ms, Hand free Speaker Phone Support Voice Gain Setting, VAD, CNG DTMF:Support SIP info, DTMF Relay, RFC2833 ... /pickup/join call/click to dial/call park SIP support SIP domain, SIP authentication (none, basic, MD5), Peer to Peer ... upgrade firmware or configuration file) Support Syslog voip phone sip phone ACOM IP ...