Hi, during checking example application "ConferenceTransfer" i see that two calls can be merged to conference.
Is it possible with this mechanism to create call between two external numbers ? Something like :
1) Create first call Call1.connect(terminal, terminalAddress, externalNumber1)
2) After establishing connection held it, create second callCall2.connect(terminal, terminalAddress, externalNumber2)
3) Call1.conference(Call2)
4) Somehow release connection for teminal , to create next conference
Is this scenarion real with jtapi ?

Joining together two outbound trunked calls is possible via the strategy you state. However it is dangerous to drop out the local party. This has to do with reliable disconnect supervision across a network. If the network does not reliably send disconnect indications back along the network path to the PBX you can lock up the trunks. Communication Manager in its default configuration will block this, but it can be overridden on a trunk group basis. If I recall properly, there is also a system level configuration item (probably in the change system-parameters features form) that blocks or allows trunk to trunk transfer (which this is a form of and that flag controls). At a minimum you should leave a local station involved in the call. You can use "phantom stations" aka X-port stations or DMCC devices (virtual stations) for that purpose.

The local station allows the application to maintain control over the call and drop it should there be a need (e.g., excessively long holding time).

Thanks for the info !
For testing i received two numbers. One of this is real device. Creating call with this number was without any problem, but its "real" call. Second number is "virtual" as was said to me. Is this "virtual stations" as you mentioned ? With this number i've got problem when trying create call, receiving csta error 21.

station probably isn't registered (look at SAT: list registered ip-station output) or isn't configured properly for CTI services (IP Softphone enabled, and station type is speakerphone equipped). Using a virtual station still requires that something (A DMCC device) be registered to it.