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Community Member

Transcoding.... :)

Good Morning all! long time since ive been on here, so i hope someone can give me some strong advice.

We have a situation on our WAN where callers at a site ring out through our gateway at the HQ, this uses the g711 codec but i would rather that they used g729 to conserve BW and then g711 outwards from there... Im assuming ill need to transcode on the gateway? does anyone have any advice for me or a direction that i could be pointed in :)

Thanks in advance..

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Super Bronze

Re: Transcoding.... :)

Hi

You only need dedicated transcoders when you need to run G729 from a device that supports G729 to one that doesn't (e.g. some application servers - Unity, IPCC etc.)

As your gateway (assuming it's an IOS gateway) will support g729, you just need to ensure it has sufficient DSP capacity.

You have PVDM2 modules in the modern gateways, for example if you have a 24-channel T1 you may have a PVDM2-32 equipped. This has 32 channels of DSP, and each G711 call will take one DSP channel. A g729 will take two.

If you equip twice as many channels of DSP as you have available channels on the PSTN, you should be fine.

If you want further help post a show diag/sh run.

Regards

Aaron

Please rate helpful posts...

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!
3 REPLIES
Super Bronze

Re: Transcoding.... :)

Hi

You only need dedicated transcoders when you need to run G729 from a device that supports G729 to one that doesn't (e.g. some application servers - Unity, IPCC etc.)

As your gateway (assuming it's an IOS gateway) will support g729, you just need to ensure it has sufficient DSP capacity.

You have PVDM2 modules in the modern gateways, for example if you have a 24-channel T1 you may have a PVDM2-32 equipped. This has 32 channels of DSP, and each G711 call will take one DSP channel. A g729 will take two.

If you equip twice as many channels of DSP as you have available channels on the PSTN, you should be fine.

If you want further help post a show diag/sh run.

Regards

Aaron

Please rate helpful posts...

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!
Community Member

Re: Transcoding.... :)

Cheers Aaron! so the other question is how do i stop the phone from turning to g711 and rather staying with g729? dial peers? as im on h323?

Community Member

Re: Transcoding.... :)

Ignore that question i realized that its under the codec preference :) thank you for triggering my slooooow brain :)

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