It would be good that the uaCSTA is not set up automatically by the 3CX leaving the opportunity to the administrator to disable it. This option could be interesting when the SIP does not support several uaCSTA. The case is encountered with Yealink phones if the IP of an auxiliary uaCSTA server is the same as the IP of the 3CX. Although it is an error of the SIP phone to not support this situation properly, the option on the 3CX could be good. After all, if we decide to make 3CX the call server, we don't decide to make 3CX the uaCSTA server in every situation.