A client has some audio issues with unsupported IP phones that connect through an SBC. (gigaset N300IP en N510IP) Looking into the problem I want to know what other phones make use of this exact SBC and if they have problems as well. Now when I look at the Phones node in the 3CX management console I can see some 3CX phone clients as: SBC:3CXPhone for windows 8 xxxxxxx and in the IP column I can see 192.168.1.15 via SBC 192.168.1.99 While other 3CXPhones show up as: 3CXPhone for Windows 14xxxxx and in the IP column it shows 192.168.1.19 without any mentioning of the SBC. Can I conclude that the people that go through the SBC must have configured this by themselves? (We did not install it for them) Or is it possible that somehow in certain circumstances 3CXphones connect themselves unto the SBC? (as far as I knew they don`t) And my final question is: The Tunnel that the SBC will set up is the same (kind of) Tunnel as the 3CXPhone clients use without the SBC?