Hi, I registered a SIP trunk provider for my account, but since it doesn't support SIP transfer I cannot use the SIP transfer function. Now this SIP trunk can also be registered in PBX system, but I wasn't able to use the domain, username and password provided in order to register in the system. May I ask if you guys support PBX system credentials for Vapi?

@Commi most PBX systems don't support

SIP Refer

- so even if you do register with the system, there is a chance this will not work. What PBX system are you using?

It's build on FreeSwitch, the system itself already has SIP REFER as the system can already transfer call already

Transfers in a PBX don't use SIP Refer in most cases, they use 3-way calling and call forking. I don't remember how FreeSwitch does it, I abandoned freeswitch completely almost 10 years ago.

Ah I see, I will test it out once I am able to registered the system credentials. Thankss