@scottalanmiller hi just to let you know I've been looking at opus on Yealink today with out VoIP system which isn't 3cx and I don't know about 3cx so this may or may not apply, and may or may not be easily rectifiable for you, depends how easily you can alter provisioning templates.

I saw that opus was in the web GUI of the phone before it was provisioned on the system. After provisioning: no opus, it was completely missing from both lists for account 1. Look at the codecs for an account you haven't provisioned, it should be there, this will help prove it's available on your phone model and firmware version.

On our system the auto provision system specifies codecs and their preference as part of the provisioning. What I found was that this list didn't include opus, so in the web GUI of the phone, opus was in the list for account 1 until I auto provisioned it. After that, opus was not available to choose.

The test was to open the auto provision config file in a web browser, for me http://URL/Mac_of_phone.cfg and in here I could see the codecs but no mention of opus. The format was also the older format for Yealink autoprovision. (If you are tftp then it's worth finding a tftp client and download the config to check it - don't forget to check the common model file y0000000x.cfg too, if 3cx uses it).

Eg:
account.1.codec.1.enable = 0
account.1.codec.1.priority = 1
account.1.codec.1.payload_type = PCMU
account.1.codec.1.rtpmap = 0

account.1.codec.2.enable = 1
account.1.codec.2.priority = 2
account.1.codec.2.payload_type = PCMA
account.1.codec.2.rtpmap = 8

account.1.codec.3.enable = 1
account.1.codec.3.priority = 3
account.1.codec.3.payload_type = G729
account.1.codec.3.rtpmap = 18

The fix for me was in our auto provision system to add these two lines, so the phone knew about opus and used it highest priority.

account.1.codec.opus.enable = 1
account.1.codec.opus.priority = 0

This is the newer provision format for firmware v81 onwards. After adding these lines opus showed up as top of the list of codecs in use.

If you prefer to stick with the older format, the rtpmap for opus is I think 107, it is mentioned in the Yealink administration guide which you'll find on the website under extra docs for your phone. It also mentions another option which is the bandwidth for opus to use, namely narrowband, wideband or fullband - which are applicable to different models differently - eg their conference phone supports FB but none of the desk phones do, only wb, which is why I didn't bother with that setting.

So the answer for me at least was opus was removed from the web GUI because the auto provision file didn't mention it, so the phone doesn't show it as an option.

Hope this helps - I registered just to post this for you!
Jon

@JaredBusch for me, brand new phones out of the box never been used before, never been configured, they were not firmware upgraded nor downgraded. The option was there in the web prior to auto provision, not afterwards. Nothing to do with upgrading firmware in my case although I take on board what you're saying about factory default after firmware upgrade being a good practice.

On the T40G phones we've just had it says 'opus' on the screen when using opus for a call; instead of 'HD', which is what you get with G.722.

Sadly, it's my understanding that one of significant reasons for using opus, namely the FEC, is not implemented in Yealink currently. Not any other hardware VoIP phones either (from my limited research - happy for someone to prove me wrong?) I only found mention of it on the Yealink video conference units. And in some mobile soft phones.

@JaredBusch I had the issue a few months back, I did default the phone, it wasn't until yesterday I actually worked out what was going on with it.

I'm not sure 'corrupted' config us a fair thing to say; it did work and was perfect for older models. Incorrect config is more accurate. Outdated maybe more accurate. It's just that normally incorrect config doesn't hide things from the GUI.

@scottalanmiller hi just to let you know I've been looking at opus on Yealink today with out VoIP system which isn't 3cx and I don't know about 3cx so this may or may not apply, and may or may not be easily rectifiable for you, depends how easily you can alter provisioning templates.

I saw that opus was in the web GUI of the phone before it was provisioned on the system. After provisioning: no opus, it was completely missing from both lists for account 1. Look at the codecs for an account you haven't provisioned, it should be there, this will help prove it's available on your phone model and firmware version.

On our system the auto provision system specifies codecs and their preference as part of the provisioning. What I found was that this list didn't include opus, so in the web GUI of the phone, opus was in the list for account 1 until I auto provisioned it. After that, opus was not available to choose.

The test was to open the auto provision config file in a web browser, for me http://URL/Mac_of_phone.cfg and in here I could see the codecs but no mention of opus. The format was also the older format for Yealink autoprovision. (If you are tftp then it's worth finding a tftp client and download the config to check it - don't forget to check the common model file y0000000x.cfg too, if 3cx uses it).

Eg:
account.1.codec.1.enable = 0
account.1.codec.1.priority = 1
account.1.codec.1.payload_type = PCMU
account.1.codec.1.rtpmap = 0

account.1.codec.2.enable = 1
account.1.codec.2.priority = 2
account.1.codec.2.payload_type = PCMA
account.1.codec.2.rtpmap = 8

account.1.codec.3.enable = 1
account.1.codec.3.priority = 3
account.1.codec.3.payload_type = G729
account.1.codec.3.rtpmap = 18

The fix for me was in our auto provision system to add these two lines, so the phone knew about opus and used it highest priority.

account.1.codec.opus.enable = 1
account.1.codec.opus.priority = 0

This is the newer provision format for firmware v81 onwards. After adding these lines opus showed up as top of the list of codecs in use.

If you prefer to stick with the older format, the rtpmap for opus is I think 107, it is mentioned in the Yealink administration guide which you'll find on the website under extra docs for your phone. It also mentions another option which is the bandwidth for opus to use, namely narrowband, wideband or fullband - which are applicable to different models differently - eg their conference phone supports FB but none of the desk phones do, only wb, which is why I didn't bother with that setting.

So the answer for me at least was opus was removed from the web GUI because the auto provision file didn't mention it, so the phone doesn't show it as an option.

Hope this helps - I registered just to post this for you!
Jon