4.2 Information on calls

Information on calls is sent by PBX in the form of statuses of the individual call-legs. So, if there is a call made in PBX between party A and party B the PBX will send two messages. One for call-leg with party A and the second for call-leg with party B. Each call-leg has its unique ID and also the list of all opponent IDs. This can be used to find out who talks with whom. This unique ID is also used in messages for switching, holding, rejecting, etc.