Mobile call coming while 3cx call is established

[AWS2P]

A customer send me this case:

when we are on a call on 3CX and there is someone calling us on our mobile, the phone does not consider that we are on a call.
In fact, the cell phone will vibrate with the ringing and incoming call displayed while talking with a customer on 3CX. Suddenly we can no longer hear anyone, the customer has lost us, the time we send the mobile phone call has hung up limit. Suddenly, the mobile caller reminds us immediately, crossover on 3CX, etc ... it's very annoying.
Wouldn't there be an option to activate (I couldn't find anything on the app), so that the phone can detect that we are in communication on 3CX, and suddenly our mobile calls go to voicemail as long as are we on the phone on 3CX?

the phones are samsung galaxy note20 ultra5g.

Is it something to do to prevent that case to occur?

 

[JohnS_3CX]

So long as the OS has the ability to take audio focus away from apps, this is not possible.

In iOS where the CallKit exists, you can gracefully manage calls and have a cell call ring as a 2nd call.

In Android the OS decides, and always remember that each manufacturer can customize the OS to behave differently than the "default Google" way (if there was such a thing).

So for now, I would say this remains impossible

 

[MidiTélécom]

In France, when users are in LTE (4G) and a call coming, the network goes form LTE to H+ and make the communication cut for couple of second, when the call is refuse, the same thing happen form H+ to LTE.
This change make the 3CX app reconnect and cut the audio between the two phone.

Is this a common thing in other country ?

 

[JohnS_3CX]

In France, when users are in LTE (4G) and a call coming, the network goes form LTE to H+ and make the communication cut for couple of second, when the call is refuse, the same thing happen form H+ to LTE.
This change make the 3CX app reconnect and cut the audio between the two phone.

Is this a common thing in other country ?

That's an entirely different subject, but yes, this also happens elsewhere. The reason is that GSM voice does not exist on LTE and the mobile phone needs to connect to H+ or lower in order to receive the call (which can interrupt the internet connection, and 3CX calls that rely on internet).