No MOH while using Opus


Anyone using Opus and can see if they have the same issue?

I am currently running UCM 6102
Grandstream 2160’s
GS Wave ver on Android 8.0.
Zoiper 2.7.12 on Android 6.0.1.

I can successfully place a call between any of the extensions using Opus and the sound call quality is outstanding!! BUT… when placing a call on hold, no hold music plays… I’ve tried all the other codecs and they all play hold music fine. The problem only happens when using the Opus codec.

I am using custom hold music, but I don’t imagine that to be an issue because the hold music works fine on all the other codecs.

This is not a new issue for me… Back in 2017 I tested out the Opus codec and had this exact same issue as well as some others. Today I was giving it another shot hoping that Grandstream had got this figured out…


I have the exact same problem when using OPUS!

  • UCM6202 v1.0.18.19
  • GXP1782 v1.0.1.79 (same with .74)
  • GXV3370 v1.0.1.43 (same thing happens)

No MOH on parking lots nor on hold.


I am surprised there wasn’t a post about this issue here on the forum.
Back in October 2017 when I 1st encountered this & opened a ticket I was running UCM 6102 using FW, GXP2130, & Zoiper Softphone 1.53 for Android.

Today I went into my ticket from 2017, and submitted a new packet capture and asked them if there is a fix for this issue yet… I will keep you posted on what they say…

Did you open a ticket about your issue?


I did not open a ticket since I don’t use OPUS in prod environment. I was testing it in my lab and discovered this issue. That’s the reason I always use G722 instead.

I can provide a capture too if needed. My payload types for OPUS are all set to 123.


I am also using the inferior G722 due to OPUS not working correctly.

It may be worth you opening a ticket for this due to the fact that my 6102 is EOL, and support may tell me that due to my EOL old hardware they are unable to issue new FW fixes for this… I see you have the 6202, so that excuse would not apply to you…


a problem is a problem and it is right to report it


I will do so.


Thanks, Please keep us posted! I will do the same…


@fmarcoux96, Also include a backup config and username and password of your UCM when you open the ticket. That is what support has requested on my ticket.


They made me do a small test:

When on the “Music on hold” page of the UCM, click the Play button of a music file and select the device in OPUS. See if it plays or not. Mine does even when parking lots and hold doesn’t play it.


When you did your test, did you make sure all the other codecs were removed? If not, the call will connect and play the MOH using a different codec.

When I did the test and made sure no other codec was available, the test failed…
I was not able to receive the MOH when I selected “Play” then selected the extension that only has OPUS as a codec.

Also I received a UCM System Event email error that says:
SIP internal call failure! from user: PBX,to user: 1011,SIP response code: 415 An unsupported media type.

I am using custom .wav files in my UCM for hold music. I am going to see if I can located the orginal MOH files and upload them, and try this test again…


So, I opened my ticket and GS replied to me with these questions:

Could you please let me know:

  • Is this from internal calls ? or external coming from a trunk ? Can you add some screenshots about ?
  • Is this happening using the default music on hold files ? or are you adding new files into the unit ?
  • If you send the audio to reproduce directly into an extension, does it sound ok ?

My response was:

-> Is this from internal calls?
Yes it is. From one phone to another, all using OPUS. My trunk provider does not support OPUS.

-> Is this happening using the default music on hold files?
Yup default music is not playing.

-> If you send the audio to reproduce directly into an extension, does it sound ok?
I can play the music from the UCM (play on device feature) and it works. However, parking lots and hold doesn’t play music. In fact, when dialing 701, it doesn’t even says “701” before the music (which doesn’t work in OPUS).

Here the current status from GS:

I might do further testing on this behavior, and comment with Devs for future releases
But recommended is to have devices use PCMU and PCMA codecs, since for the opus could be a secondary audio codec. but main recommended is PCMU.

So @Bionic, to answer your question, no I did not. My extensions and phones are all configured with 4 codecs only ([G722, OPUS, G729, PCMU] when in prod, [OPUS, G722, G729, PCMU] in testing). I don’t get this error whatever I do. Also, I use the built-in MOH to be sure it works before testing with my own WAV files.


My phones also have about 4 or 5 different codecs assigned… When I did the test with all the other codecs available the test played fine but just skipped OPUS and used another codec…

By removing all the other codecs, you will force the phone to try to connect with only OPUS…
Once I did that, the test would fail.

Can you try to remove all codec but only opus, and see if the test will fail?


I will try next week but all the phones are configured to use the first matching codec so they should be using OPUS anyway.


But when you do the test it will skip OPUS and use a codec that works, even if it is listed 1st.

My Grandstream phones show on the LCD which codec is being used for an active call…
When I did the test with Opus listed 1st, and other codecs listed as well… The test played but the phone showed it was using 729, not opus.

Interested to see your results when you remove the other codecs!


I just though about something… I wonder can you check voicemail using opus?


I will try these things and let you know. I know calls between phones works perfectly in OPUS. However, my GXP1782 doesn’t show the codec, only HD or SD.


@fmarcoux96, What tech is helping you with your ticket? Mine is assigned to “Nathan” ticket #20171012122641. I would like to let Nathan know that there is another Tech working on the exact same issue, so that they may be able to work together more efficiently on this vs duplicating each others efforts.


Hi, mine is Daniel, on ticket #20190314185354.


Bionic -

I tested as you requested -

2135 and 3275 only set to use OPUS. Calls between extensions are fine. When call placed on-hold, there was no MOH on either phone. Resumed call and voice was fine again using OPUS.

I then used the 2135 and dialed *98 to reach voice mail whereupon I had hoped to get UCM generated greet and be asked for mailbox selection and passcode. As you can see below, the system answered RTP was started, but the UCM only sent CN and then disconnected 3 seconds later.