vMix itself will not do this. However, there are ways one can incorporate third-party systems, services, or what you currently use, to do what you want.

I've been involved in this sort of thing for many years. The podcast that I co-produce each week invites participants to connect by telephone, with access lines in about 40 countries. We use a telephone conference bridge that is connected to a Hangout.

You can use whatever service you like for IP telephony. What you need from them depends upon what you hope to achieve. Do you want to take their calls and have someone vet them before passing them to the show? If so you need a switchboard like functionality that's common in hosted PBX services. That allows someone to answer each call, put them in a queue, before they get get passed to the show.

You receive each call, put them on hold (or in queue) then transfer them to the connection that corresponds to you live studio. This is just like a receptionist.

We don't do that. We just allow people to join a conference call that's connected to the show. We can manage the conference, allowing people to speak (or not) as appropriate.

You can do this using a hardware solution like the Comrex system you mentioned, or by combining software and services. In my case, we have one sponsor who is in the conference business (http://www.zipdx.info) and another who is in the business of providing international phone numbers (http://www.voxbone.com)

Check Asterisk server for VoIP.

I can think to several ways to do this with Asterisk (mainly as Michael said):
- one is to use a conference room as Michael said
- another one is to simply transfer the selected calls one by one to the specific line that is used for the show
- another one uses the Barge feature
- etc...

All these will be full-duplex

Guillaume

I appreciate all the input -

I am going to go thru this and see if any make sense for us.

Thank you.