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voice-class codec vs. codec g729r8?

Previously, I had voice-class codec 1 configured on a VoIP dial-peer which had preference 1 set to g729r8 and preference 2 to g711ulaw. After doing a sh voice dsp active, all calls were being negotiated in g711ulaw.

When I changed from voice-class codec and forced g729r8 using the 'codec g729r8' command on the dial-peer (forced to remove the voice-class codec command), calls began negotiating in g729r8.

1. Although calls are being negotiated in g729 now, this is dependent on the protocols that are supported by the remote end correct? If so, and the remote end does not support g729, what will happen to the call?

2. Can anyone figure out why the command voice-class (shown below) failed and only the codec (dial-peer) command successfully negotiated the calls in G.729?

voice class codec 1

codec preference 1 g729r8

codec preference 2 g711ulaw

Thanks in advance!

Community Member

Re: voice-class codec vs. codec g729r8?

If you allow only one Codec then only that codec will work from an H.323 gateway. Where were you trying to dial to? Direct to another gateway? Through CallManager to another gateway? Through a gatekeeper? To an IP phone through CallManger? To an ATA device configured in Call Manager?

If CallManager is involved what is your region settings set at?

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