Solved No audio on internal attended transfer.

[NathanD1337]

• 3CX Version, Professional Annual 18.0.1880
• Server OS, Debian
• Is the 3CX Server Hosted and where? - Digital Ocean
• IP Phone Make/Model/Firmware version, Yealink T48s - Fw 66.86.0.5
• Provisioning Method: STUN
• Has the Firewall Checker passed: YES
• Are custom Phone Templates being used: NO

Hi all,

All phones are yealink t48S and we have a few ios apps also.

When making an attended transfer anyone using the Yealink phones get no audio on the calls however if the yealink makes an attended transfer to the ios app the yealink user can hear the ios user but the ios user cannot hear the yealink user.

The only thing that has changed was that the yealink phones got a firmware upgrade to the latest version.

I have downgraded two of the phones to an older version (66.84.0.80) But this has not made a difference.

Any ideas?

 

[Evolute IT]

"PBX Delivers Audio" and port forwarding are my guesses here.

 

[NathanD1337]

Update--

Fixed by enabling PBX delivers audio on the yealink extensions

SIP Trunk Pbx audio was already enabled.

 

[NathanD1337]

"PBX Delivers Audio" and port forwarding are my guesses here.

Thanks haha to be fair didn't think of doing it on the extensions as it was already enabled on the sip trunk but worked a charm.

 

[Evolute IT]

Thanks haha to be fair didn't think of doing it on the extensions as it was already enabled on the sip trunk but worked a charm.

It's not the same option. The setting on the trunk will be enabled 99% of time.

The one on the extension is mostly disabled except when using STUN.

 

[ChrisC_3CX]

Glad to see this got resolved, but, do consider switching to a 3CX SBC configuration if you have more than a couple IP Phones on the same remote location(s) to avoid these kind of issues in the future.

If switching to the SBC provisioning method is not possible, just make sure that you have configured STUN correctly as mentioned in the guide provided by @Frederick Marcoux.