3CX internal calls audio and port management

[Alle CTEC]

I have a question that is not clear to me, 3CX V20 internal calls are made through the pbx, so the phones need to communicate only with the pbx or must they also communicate with each other. Classic scenario or internal 1 and internal 2 center PBX A, 1 talks to A and 2 talks to A, 1 to talk to 2 uses A and vice versa?

Or 2 PBXs in trunk A & B internal 1 PBX A must talk to internal 2 PBX B 1 and 2 communicate via A and B or do they use them to raise the call and then talk to each other?

 

[Alle CTEC]

my interest is in configurations between pbx in trunk without audio delivery via pbx. If I use VPNs then I have subnet A connected in VPN with subnet B or I have a single PBX A and a remote subnet B connected in VPN which ports should I open if I don't use audio delivery via PBX UDP 9000:10999 are for external calls, but for internal calls are they UDP 7000:8499?

 

[NicholasP_3CX]

The calls are established and negotiated between the devices and the PBX... Always.

The audio on local devices, even through a VPN can be directly from one device to another. Alternatively you can force the audio to go through the PBX by enabling PBX delivers audio, or by enabling recordings.

PBX delivers audio helps alot in cases where remote VPNed networks do not have direct access between those sites and they have to go through the main site which does have routing access.