... , 2SIP accounts, 3way conference call, full duplex hand-free speaker phone, support SMS Features: Support SIP 2.0 (RFC3261) and correlative ... .168, and Hands-free can support 96ms, Hand free Speaker Phone Support Voice Gain Setting, VAD, CNG Full duplex hands-free ... (none, basic, MD5), DNS name of server, Peer to Peer/ IP call SIP support 2 SIP lines. Can connect to SIP1 ...