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New Member

Silence when Leaving messeges, Unity4.02 Codec problem??


I'm having a bit of a problem with our current unity install. When a user at a remote site recieves a call from the PSTN (G711) and it goes to voicemail at our Headoffice (g279) the message a user gets is just silence. The message only has silence.

I have changed the Voicemail to remote sites to G711 and the messages are ok. Only the ones recorded as g711.

At our headoffice when using G729 the messages are ok.

How do you change the coden Unity uses to G729??

Can anyone help?



Cisco Employee

Re: Silence when Leaving messeges, Unity4.02 Codec problem??

I'm not sure I have a complete grasp of the problem you're having here but for Unity to handle G729a codec you need to install it (it's not installed by default since it's a 3rd party codec).

to install it you need to run sl_g729a_setup.exe found under the commserver\utilities directory. Once this codec is installed Unity will be able to record messages in G729a - you set the recording format system wide using the SetReocordFormat tool found in the tools Depot on your desktop. This changes the format for ALL records to be what you select - by default this is 711.

When a call comes in, if Unity is set to record 711 and the call negotiates 729a, unity will transcode into 711 on the fly (you have to have the 729a codec installed for this, of course). And vice versa.

New Member

Re: Silence when Leaving messeges, Unity4.02 Codec problem??


I have the same problem but with a Spectralink phone going through a transcoder. The Spectralink could only use g711 and it is converted to g729 through the transcoder (a Cisco 3640 router with NM-HDV). The message left on Unity is silence. I have enabled g729 on Unity using the utilities. The problem is not there if the message is recorded from an IP phone which is also g729.

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