1. Protocols, NAT Traversal
SIP(RFC3261) \ STUN Codec Voice Quality \ G. 711 u-Law \ G. 711 a -Law \ G. 723.1 (5.3k/6.3k) \ G. 729(A/AB) \ G. 726(16k/24k/32k/40k) \ GSM \ VAD \ CNG \ AEC, LEC \ Packet Loss Compensation \ Jitter Buffer

2. Telephone Function, Call Function
Normal PSTN phone(No battery support) \ PSTN Phone \ VOIP Phone \ Volume Adjustment \ Speed dial key \ Phone book \ Redial \ Flash \ Speaker Phone \ 3-Way Conference \ Hot line \ Call Hold \ Call Waiting \ Call Forward \ Call Waiting \ Call Mute \ Caller ID(FSK/DTMF)

3. Tone, DTMF Function
Ring Tone \ Ring Back Tone \ Dial Tone \ Busy Tone \ User Programming Tone \ DTMF Detection \ DTMF Generation \ In-band DTMF \ Out-of-band DTMF(RFC2833)? SIP Info

4. FAX Function, Dial Methods
T. 38 \ Direct IP Call w/o SIP Proxy Dial number via SIP server

5. Configuration, Firmware Upgrade
Web browser \ Console/Telnet/Keypad \ Auto-Configuration \ TFTP \ Console \ HTTP Auto-Provision

6. TCP/IP, IP Assignment
IP/TCP/UDP/RTP/RTCP/ICMP/ARP/ RARP/SNTP \ TFTP/PPPoE Client \ DHCP/DNS Client \ Telnet/HTTP Server \ IEEE802.1 P/Q \ Tos/Diffserv \ NAT/DHCP Server \ Static IP DHCP