2. LSW-502: Support SIP2.0 (RFC3261), TCP/UDP/IP, RTP/RTCP, HTTP, ICMP, ARP/RARP, DNS, DHCP, NTP, PPPoE, STUN, and TFTP etc; Inside Rooter/NAT, gateway and DMZ Port transmit; Support registered to two gatekeepers; Use the DSP CNOS chip to keeping a wonderful audio-quality, advanced shaking control, and the technology of hiding the lost massage; Support kinds of voice coding, including G.711 (alaw and u-law) G.723.1 (5.3K/6.3K) G.726 (40K/32K/24K/16K), G.729A/B, and iLBC; Support incoming call on show, restricting, and holding, disconnection, call transfer, call divert, DTMF, dialin Support passing through and T38 fax, voice restrain and jerquers, CNG, echo restrains (G.168), AGC, and DIGEST using MD5 and MD5-sess; Support layer 2 (802.1Q VLAN, 802.1p) and layer 3 (QoS, DiffServ, ToS); Support NAT auto- penetrating, no need to modify the setting of the NAT; Support configuration files by inside IVR equipment, Web browser, or TFTP and HTTP Center Server; Support upgrading encrypts configuration files by TFTP or HTTP; Microminiaturize and legerity design (size as a wallet), a adapter that convenient for schlepping