Cannot transfer to phone after call pickup from that specific phone

[Nathan Kestier]

Hi guys (and girls),

we are having some trouble with hosted 3CX instances (it doesnt happen on local 3CX servers).

The problem:

• Incoming call on phone A
• Phone B does a call pickup through BLF
• Phone B wants to transfer the call back to phone A through BLF
• Phone B presses the BLF of phone A
• The call ends immediately (no transfer is made - the call is gone/hangup)

We have this issue with 2 clients at this moment, both clients work in the cloud (hosted) and with an SBC connected.
They are using a Professional Annual 16.0.0.1581 license (fully updated).
The clients are working Yealink T46S devices in firmware 66.84.0.35.

Happy to get some insight of the almighty forum dwellers.

Thanks in advance,
Nathan.

 

[JohnS_3CX]

Hi Nathan,

1. Can you give some more information about how the BLFs are set up? i.e Under provisioning is normal "BLF" selected or is it "Speed Dial", "Custom Speed Dial" etc?

2. How is the transfer done exactly? i.e after B does the pickup and now has the active call running, do they first press "Transfer" and then select the BLF called "Phone A" ? Or do they just press the BLF directly without first pressing Transfer?

 

[Nathan Kestier]

Hi JohnS,

thanks for the quick response.

1. The BLFs are setup as "BLF" (not SpeedDial or Custom SpeedDial).

2. After B does the pickup and has the active call, they don't press 'Transfer' but instantly press the BLF called "Phone A".

 

[JohnS_3CX]

Ok I replicated your scenario with the same firmware and PBX version, and I tried with PBX delivers audio on and off for both phones. I ran it on a Windows 3CX SBC v15.5.7503 which is the latest version available for download. Everything checks out fine with no dropped calls.

Can you confirm your version via the 3cxsbc.conf file, and also test with PBX delivers audio both in ON and OFF mode? This can be changed under each extension's Options tab

 

[Nathan Kestier]

Its not possible (yet) to check the firmware on the SBC, we are working on this (i will get this next week).

At the moment we do not have "PBX delivers audio - ON" (its OFF).
We're going to test this while its ON and get back to you.

Thanks for the quick support.

 

[JohnS_3CX]

You're welcome Nathan, let us know how it goes and also let us know what SBC you are using (Windows/Linux/Pi ? and its version)

 

[Nathan Kestier]

Hey JohnS,

Windows SBC
Unifi Cloud Key V0.13.7
Unifi Version 5.10.19-11646-1


We will be testing "PBX delivers audio" tomorrow, feedback will follow.

 

[JohnS_3CX]

Are you running an SBC instance off the Cloud Key?

 

[Nathan Kestier]

Yes we are.

 

[JohnS_3CX]

Hi Nathan,

Ok since this is not officially supported we don't know how it can affect the system, I would recommend to install the SBC on a regular PC without any other software running on it and then testing again (you can use our Debian ISO).

 

[Nathan Kestier]

Hey JohnS,

that sucks to hear, all our hosted clients (+50) are using SBC on a Cloud Key.
Our partner TechWare (Belgium) delivers this to us without any problems (so far).

Its strange this would influence the problem we have since all our other clients are working just fine.

Our client will be testing "PBX Delivers Audio" today, I will send you feedback on that.

 

[JohnS_3CX]

Ok, and if that solves it then the issue may be unrelated to the SBC and more related to the LAN.

Regardless, it would be best to run some captures and learn precisely what happens.