Unique ad-hoc conference need - any ideas?

[fthomas_mcallen]

I have been scouring the forum and testing different things in my environment, and I can't figure this one out. Here are my environment details:
3CX v18u9 (Debian) On Premise
Yealink T57w phones (latest supported firmware)

I have a customer who has a rather unique need as follows. The context is serving medical clinic patients in person with a language barrier:
1. Front desk personnel places a new external call to an interpreter service, uses DTMF inputs to select a language, and is connected to an interpreter.
2. Front desk personnel presses 'conference' on the desk phone and adds a second internal extension to the conference. The patient picks up this extension and can speak to the admin person and the interpreter at the same time (three-way ad-hoc conference)
^^ This all works fine.
3. Now the patient is checked in and taken to an exam room. At this point, the admin person needs to transfer the established conference call to the exam room extension so that the three-way call can continue between the doctor, the patient, and the interpreter. Basically the doctor needs to replace the admin person on the call.

I can do this easily if the initial call (Step 1) is made using the PWA softphone --just hit transfer and enter target extension as normal. I cannot figure out how to do it using only deskphones. What I am finding is that when the person who initiated the call hangs up, the whole conference drops. The transfer key on the Yealink phone does nothing when in a conference.

I have tried a custom config on the Yealinks to explicitly set the account.1.conf_type = 0 and transfer.tran_others_after_conf_enable = 1 parameters. This did not change the behavior, although I thought it would.

Does anyone know if this is possible? Thanks for any help you guys can provide.

 

[SweetAction]

When using the PWA/Apps, the conference happens on the 3CX server side. This has the downside of stuff like losing DTMF on all connected calls (if you called the interpreter service second, you would not be able to select a language), but the upside of 3CX owning that conference and being able to transfer it.

When using a T57W, the conference happens on the phone itself. Upsides include working DTMF for all connected calls, but downside is that phone owns that call. That phone hangs up, that call ends.

This boils down to the endpoint - when 3CX Apps are used, they use the server, and when T57W is used, it uses itself.

You should open a case with Yealink on how to solve this. I'm sure there is some sort of config that can be set, but I don't know what it is.

 

[fthomas_mcallen]

Thanks. I understand the difference between using the PWA and the deskphone. I just wondered if any partners had found a creative way of making something like this work. Unfortunately, we still have quite a few clients that are much more comfortable pressing keys on a phone than they are with a software interface as their main "phone"

 

[SweetAction]

Because this issue is due to the yealink owning the call, contacting yealink support should give you next steps. You are looking for a way to transfer a conference call and 3CX plays no role in this - it's all up to the Yealink IP phone.