dsp calculator issue

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Nov 20th, 2007
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i am confused with dsp calculator when determine the type of call i don't know which i have to choose the flex codec or the medium codec or the complex codec



i want to know also what type of codec that the pstn use

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allan.thomas Tue, 11/20/2007 - 08:36
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By default when you configure DSP resources the codec complexity is set to medium, only configure flex if you require higher call density, typically G711ulaw for PSTN calls.


Medium or High codec complexity requires more DSP resources such G729ab


If you do not intend to use DSPs for anything other than PSTN calls and no transcoding or conferencing, then simply specify the same number of G711 voice calls for what is supported on your voice module.


For example a VWIC2-1MFT-E1T1-E1 supports 30 voice calls, you would then specify 30 G711 calls.


Allan.


Pls rate this post if you find it helpful.

mostafamossad Wed, 11/21/2007 - 06:53
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thanks

i need to know why someone may need to make the E1 that connect to pstn work in medium complex mode (g729)

why i choose g729 in case i can use g711 in case i connect to the pstn

allan.thomas Wed, 11/21/2007 - 07:11
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As mentioned previously the codec complexity would be configured as medium by default, therefore this would not have changed.


You would be required to configure flex complexity if you were using G711 for voice calls, and did not require conferencing/transcoding resource for low bandwidth codecs such as G729a, G729b.


I suspect that although flex complexity has not been configured your voice call are in fact still G711. When a call is established on the PSTN voice gateway run 'show voice call summary' this would indicate what codec is being used.


If you are not providing DSPs for low bandwidth transcoding or Conferencing, the configure your DSPFARM for FLEX.


Regards

Allan.

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