Yealink SIP-T2XP Administrator's Manual page 481

The following figure illustrates successful 3-way calling between Yealink IP phones in
which User A mixes two RTP channels and therefore establishes a conference between
User B and User C. In this call flow scenario, the end users are User A, User B, and User
C. They are all using Yealink SIP IP phones, which are connected via an IP network.
The call flow scenario is as follows:
1. User A calls User B.
2. User B answers the call.
3. User A places User B on hold.
4. User A calls User C.
5. User C answers the call.
Appendix
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