Protocol: 1) SIP call signaling-FC3261 with backward compatible with RFC2543 2) RTP (RFC1889), RTCP (RFC1890) 3) SDP (RFC2327) 4) NAPTR for SIP URI lookup (RFC2915) 5) Messaging Waiting Indicator (RFC3842) 6) DHCP 7) PPPoE 8) Web management 9) TFTP for auto provisioning Voice processing: 1) CODEC: G.711 (a-law and u-law), G.723.1A and G.729A, G.729AB 2) Acoustic echo cancellation 3) VAD (voice activity detection) 4) CNG (comfort noise generation) Call features: 1) Mute stop or resume voice transmission 2) Volume adjustment: +/- the volume of handset, speaker and ringer 3) Message LED: 2-color LED message indication 4) DTMF relay: supports in-band RTP voice mixing and out-band DTMF over RTP (RFC2833) 5) Speaker phone, handset-free, and ear phone supported 6) Calling/called Caller ID 7) Dial tone, DTMF generator, ring back tone, busy tone, disconnect tone, and ring tone 8) Redial 9) Call forwarding 10) Call waiting 11) Call hold 12) Call transfer based on draft-ietf-sip-refer-07.txt 13) Call rejection 14) Call screening 15) 3-way conference on the phone 16) Auto redial 17) Speed dialing 18) Call history: a) Most recently missed calls b) Most recently received calls c) Most recently dialed numbers 19) Multiple outbound proxy, registrar and redirect server support, up to 3 different service domains