The Opal SIP implementation supports the following standards:
- Basic SIP call handling
- Re-Invite support as per RFC 3264 "An Offer/Answer Model with the Session Description Protocol (SDP)" including:
- Call hold and resume by adding/removing media streams
- Codec change by re-INVITE
- Call control support (PBX/telephony emulation, e.g. blind/consult transfer etc)
- Media & RTP
- DTMF support
- Audio
- Video
- Data support
- Presence & Instant Messaging
- Miscellaneous
- Not yet implemented