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TTS codec question on IP IVR

I all,

just a simple question I hope...

I've CUCM 8.5.1 with IP IVR 8.5.1 (UCCE is not important in this problem) in our test environment.

In IP IVR System Parameters I have G729 as codec setting.

I've installed and configured Nuance TTS system; the TTS subsystem is correctly "In Service" state.

If I debug the IVR script, on the PlayPromt(TTS["this is a test"]) step, it raises the error: Expected audio format tag: G729, found audio format tag: G711_ULAW

It seems that TTS cannot work with codec G729 and this is confirmed by Nuance; so, I need something that make transcode on the audio stream "on the fly"...

I tried to configure a transcoding resource on CUCM (either "standalone" or inside a MRGL/MRG) but it seems that CTI Port never call it...In RTMT I can see the Transcoding resource ever with 0 Active...

So I'am wordering if it is possible to use TTS on IP IVR configured with codec G729 and if yes, how.



TTS codec question on IP IVR


does the MRGL of the CTI Port(s) include the Transcoder? Also, is the Transcoder accessible, I mean, no bandwidth limitation etc.

Also, can you please tell us more about the Transcoder itself? Does it kick in in a different situation (e.g. a phone calling a UCCX application, while the phone is restricted to use the G.729 codec only)?


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TTS codec question on IP IVR

Hi Gergely,

thanks for fast reply...

In this moment I have no MRG/MRGL configured; so, it should be available to all devices... it isn't true?

BTW, the transcoder have no bandwidth limitation... but Region and Device Pool configurations are very very intricated...

I tried to understand them but I'm afraid that I miss something.

Unfortunately in this Customer's test Environment, everyone can add own "caos".

So, for my safety, next week I will configure a Transcoder in my Company test environment and I'll replicate the test.

In any case do you think that is possible to use TTS with IP IVR in codec G729, yes??

Next week I'll update this post.

Thanks a lot for now,


Re:TTS codec question on IP IVR

Hi, I did not test this myself, but I believe that it should be possible.

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