Hi all: I know that the example uses REFER sip method and follow such process: 1. prepare two SIP softphone(eyebeam 1.5.16.1 ) , register to openser 2. user enter Caller and Callee's SIP Address 3. Web Server receive http request, then construct FIFO command, using t_uac_dlg MI command, build Refer SIP message with From and To header using user input 4. t_uac_dlg is invoked, send sip REFER message to Caller Sip softphone, softphone return 481 Call Leg/Transaction Does Not Exist, so the call can't be setup. I have seen the notice"/Unfortunately, this example does not work. The reason is use of REFER for third-party call-control has not been standardized due to resistance of proponents of B2BUA use (which is somewhat bloated and not always operational)". But I still wonder if any softphone support this example? My openser version: 1.3.0 Thanks. Regards, Chen Xueqin /