Asynchronous Inbound to Outbound Calls

[David Mössner]

Hi Guys,
please excuse the title I do not know how I can describe my "problem" differently.

So:

given:
- SIP trunk with 6 simultaneous calls
- 3CX Pro 8 Simultaneous Calls (V15.5)

The customer wishes:
- 2 incoming calls
- 4 outgoing calls
- Now comes the 3 call, this should land on an IVR announcement that all lines are occupied ...

Solution for this:
- create 2 separate trunks (2 + 4 channels)
- 2 channels incoming
- 4 channels outgoing

So far everything is clear.

But:

How do I put the 3 call on my IVR?
I assume that I first have to set the incoming calls to 3 ... But what then?
Is there even the possibility to create such a behavior?

Thank you in advance!

 

[VoIPTools]

The only way this could be done is by routing all calls through a CFD that checks the number of simultaneous calls in use (using the Call Control API) and route accordingly.

 

[David Mössner]

The only way this could be done is by routing all calls through a CFD that checks the number of simultaneous calls in use (using the Call Control API) and route accordingly.

First Time CFD User
I Tried and failed.

Pretty sure i made a mistake along the Way ... Now the Caller gets directly the Busy Tone ...
How do i correctly access the Call Control API through CFD?

I guess i cant do it by using the 3CX Control "Get Global Property" with the "PropertyName" "session.ani"?
Becaus this is how i do it now and it leads to the Busy Tone Error

 

[leejor]

If you want to control the destination of a third call, then you must allow 3 calls to come in over the trunks. If you limit to two only, then your provider will have to "deal" with that third call (busy signal, voicemail, forward), as you have are telling them that you won't accept it.

 

[VoIPTools]

Reading your scenario again, I have to agree with leejor. If you only have 2 inbound trunks, the 3rd call is not going to reach 3CX. In the scenario where you have 3 or more inbound trunks, then my suggestion would be appropriate. Connecting to the Call Control API is not a trivial process but documentation and sample code is available here: https://www.3cx.com/docs/call-control-api/. You will have to use an external code component to query the API and have the method return the number of calls in use.

 

[David Mössner]

OK but then i have a major issue ...

According to the Documentation is this only possible on a Windows Machine?

My Instance is running on Linux from the official 3CX Image...

 

[VoIPTools]

The Call Control API and Call Flow Designer (applications) both work on Windows and Linux. Where you may have misunderstood is that the "Designer" only works on Windows, but the developed CFD "applications" will work on Linux.