DSP resource and E1 CAS problem

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Aug 25th, 2008
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Hi all,

I have one router 2811 with 1 E1 voice card and 2 PVDM2-8. When I configure E1 controller with command "ds0-group 1 timeslot 1-15 type r2-digital r2-comp ani"

I receive alarm inform that the router only has DSP resource for 12 timeslot.

Is it possible to use only these 12 voice channels to send and receive voice message? How does timeslot 16 (signaling) control remaining voice channels in this router?


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Marwan ALshawi Mon, 08/25/2008 - 05:47
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first Both the PVDM2-8 and the PVDM2-16 have a single DSP. The DSP on the PVDM2-8 has ½

the capacity of the DSP used on other PVDM2 modules

The output of the show voice dsp voice command lists the model of the DSP in use. The DSP NUM lists the number of the DSP. The DSP numbering scheme varies depending on the router platform and the NM in which the DSP is installed. The CH column indicates the DSP channel used for each physical DS0. The number of channels that a DSP can support depends on both the DSP model and the codec complexity in use, which is indicated in the fourth column of the output.

If you try to configure more voice port terminations than your DSP configuration can support, you will receive an error message similar to yours

channel 12 willl carry the sig.

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huydien3384 Mon, 08/25/2008 - 06:40
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thanks for your quickly respond!

Is it neccessary to tell the Service provider configure channel 12 will be the the signaling channel at their side? Or channel 12 will become carrying signal automatically?

Thank you very much!

Marwan ALshawi Mon, 08/25/2008 - 06:46
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u dont need

in ur case i think u should see the chnnel 16 added automaticaly

It is important to understand that the D-channel is always added to the pri-group, even if it is not explicitly specified, because it is required for signaling

for example u might u use only 4 channels when u do show run

First 4 B-channels included in the pri-group, D-channel 16 added



controller E1 1/0

pri-group timeslots 1-4, 16

good luck

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adham_tahoun Mon, 09/08/2008 - 11:33
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Hi Marwan

Is there a way to define which timeslot a D-Channel allocates ?

The issue that I have Nortel PBX uses D-Channel in the 31 timeslot, and Cisco uses 16 ... so I want both to match.

I am using E1 QSIG

Thanks Marwan


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