I ran into a problem with the sip trunk in issabel, which there is not much information about on the internet, but it seems to be a very simple solution. The sip phone settings that I received are a little different from the usual sip phone settings. In the sip phone settings delivered to me, there is a parameter called outbound proxy, and there is @ and domain in the username, and I think these parameters caused sip trunk not to run. I ran different softwares to test so that I could hear the beep of this sip phone, the only software that I could test the line correctly with all my effort was 3CX software. I will send the settings file and photos of 3cx settings here I have also managed to do trunk on Huawei FXS. If anyone knows how to run this sip trunk in issabel, please let me know. I would be grateful if you could advise me how to fill the PEER Details, USER Details and Register String sections.
Image of 3CX Config and Huawei FXS:
3Cx Config :