... and high performance VoIP phones which supports both H.323 and SIP standards. It offers lots of ... (pbx) phones. HighlightsLow cost IP PhoneBuilt-in H.323 V4 and SIP V2Built-in 3-way conferenceFull ... and desktop Key FeaturesOpen Standard VoIP Protocols (ITU H.323 V4 and/or IETF SIP V2) All ... support: English and Chinese Supported StandardsITU: H.323 V4, H.225, H.235, H.245, H.450 RFC 1889 - RTP/RTCP RFC ...