... , and Hands-free can support 96ms, Hand free Speaker Phone Support Voice Gain Setting, VAD, CNG DTMF:Support SIP ... domain, SIP authentication (none, basic, MD5), Peer to Peer/ IP call Call control features: Flexible dial map, Hotline, Empty callingn ... Black list for reject authenticated call, limit call, No disturb, Caller ID NAT transverse:support STUN client Incoming calls /Outgoing callsn /Missing ...