Performance and features
    SIP v1 (RFC2543), v2(RFC3261)
    Support Route,Two 10/100Mbps MACs
    Support T.38(Doing)
    IP/TCP/UDP/RTP/RTCP
    IP/ICMP/ARP/RARP/SNTP
    TFTP Client/DHCP Client/ PPPoE Client
    Telnet/HTTP Server
    DNS Client
    NAT/DHCP Server
    Support G.723.1 5.3k/6.3k,G.729,G.711 A-Law\μ-Law audio codec algorithm
    Dynamic voice detection Echo cancellation Comfort noise generation
    Tone generation and Local DTMF generation and detection according with ITU-T
    Settings by HTTP web browser (IE6.0)
    Advanced settings by Telnet
    Voice prompt
    Upgrade by TFTP 
    2RJ45 Ports,Built-in Router,conference.Auto-provision or updating by HTTP,FTP or TFTP.
    For each YWH600A,It can be register 3-SIP account,all can used as callee at anytime.It also can be slected among these 3-SIP account as caller by dial different dial prefix.
    For each YWH600B,it can have 3-SIP account and one PSTN phone number,that means each phone own 4 phone numbers,all can be used as callee at anytime.Fo the caller,these 4 account can be selected by dial different relevant prefix(including switch to PSTN as an ordinary PSTN phone)
    YWH600B has a real FXO port to support router call from PSTN to VOIP or VOIP to PSTN.