Unity and G.729A

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Dec 4th, 2008
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Hello All,

Does unity support G.729A? Is there anywhere in unity that I can force the codec selection like we do in the region of CCM?

I receive a call from an Avaya PBX which supports only G.729A (G3 version 12, an old version). It works fine when calling an Cisco IP phone over the WAN but sometimes the call is distined to a route-point which is sent to unity in order to verify the time of day. When the call comes back to CCM in order to be routed to the members of the route-point, it sounds fastbuy. I know somewhere there's a codec mismatch but I don't seem to be able to locate where the issue is. Anybody with any idea?

Thanks for your support,


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Overall Rating: 3.7 (3 ratings)
Brandon Buffin Thu, 12/04/2008 - 13:01
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Unity will convert from g.711 to g.729 in software on the fly. You can convert greetings, etc. to g.729 using the Set WAV Format tool in the Tools Depot on the Unity server. With the problem you describe, you might also check your partitions and calling search spaces. Make sure that the calling search space assigned to the unity ports has access to the partition assigned to the phone it is calling. Also, check the Restriction Tables in Unity admin.


Jaime Valencia Thu, 12/04/2008 - 13:17
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under the advanced settings tool you can enable G729, be aware though it supports it, it can cause some overhead so the recommendation is to use an external XCODER for this purpose and always connect to Unity using G711



if this helps, please rate

mightyking Thu, 12/04/2008 - 13:28
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Thanks Guys,

There's no CSS/Partition issues becausse when I select G.711 it works fine. but this is not the codec that I want to use over the WAN.

As I mentionned the direct G.729 calls to the IP Phones work fine. The only issue is when the CCM sends the call to unity for the time/schedule verification (Call Handler) and then unity sends the call back to CCM. Is there a way that I can verify the time of day in the CCM without sending it to the Unity and route the calls to the right directions?


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