Solved DTMF problems with Yealink T58A after upgrading to firmware 58.86.0.20

[apitsos]

Hi there!

A customer has informed us that the PIN numbers of their mailboxes were not accepted. The customer has the latest (upgraded) version of 3CX (Enterprise 16.0.8.9) and they all have Yealink T58A. I tried to disable the PIN number on a voice mailbox and then the options for the menu were not accepted!

We also have a Professional version of 3CX and it happens to have also a Yealink T58A device on our network. There was no problem at all with out device and the DTMF tones were passed to the PBX.

Then I noticed that the firmware of the Yealink T58A was different. The customer had the latest version (58.86.0.20) and we had the version 58.85.0.5. So I took the risk to upgrade to the latest one our device as well. And yes, then I got the same problem. The DTMF tones were not passed to the PBX correctly.

Is there any solution right now, or should I make a manual downgrade on all Yealink T58A of our customer? Because they are a lot.

Thanks a lot in advance for your prompt attention!

 

[NickD_3CX]

Hi!

Would you have happen to be using the Opus codec on your T58?

If yes, please remove it, reprovision the phone, then try again and let me know.

 

[apitsos]

Hi Nick,

That did the trick! Thanks a lot.

Would you be so kind to explain what this codec is and why it caused this problem?

 

[NickD_3CX]

Great!
Of course, it's a bit on the technical side, but in the new Yealink firmware, when you have Opus in the codecs, the phone sends 2 "telephone-event" lines in the SDP, one for the "classic" codecs and one with the bitrate of Opus (48k).

In V16, the IVRs don't support this, that's why DTMFs don't work.
We have addressed this in V18 though, so once you upgrade your PBX, you can go ahead and add Opus back and everything should work smoothly again.

 

[apitsos]

Hi Nick,

Thanks a lot for the quick and accurate respond. I always appreciate your support!

I am wishing you a nice day.


With kind regards,
Angelos Pitsos

 

[NickD_3CX]

You are most welcome, you too!