How Can i make conferance like this Call came from PRI And joining Called Number Conferance Room (211) While joining progress. I want to make Asterisk call sip agent for 2nd conferance person When sip agent answer then SIP agent join to room(211) 1st.Conferance Person (PRI) 2nd. Conferance Person (SIP) If sip agent busy 1st person join conf room 211 directly How can i wrote exte. For this plan