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New Member

Silence Suppression

CallManager: 3.1.1a SP:F

Phone Load P00303010408

Phone:Cisco 7960

Gateway: VG200

I am testing Silence Suppreession because management team has raised a concern that when no-one is speaking on phone during active call, it appears as though the connection is lost.

I have played with SilenceSuppressionSystemWide and SilenceSuppressionWithGateways Parameter within CallManager and when I place a call 9.XXXXXXXXXX and on the Gateway type: show call active voice

I always show VAD=Ena.... No matter if I set SilenceSuppressionSystemWide and SilenceSuppressionWithGateways = True or False.

Does Silence Supression actually work ??????

Any experience would be greatful.



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Cisco Employee

Re: Silence Suppression

Yes Silence suppression does work. Sounds to me like you are not matching the correct voip dial peer when you are going out. Try doing the incoming called-number command on the dial-peer with the no vad on it.

Thank you,


New Member

Re: Silence Suppression


I am in a test environment, and can control te number of outgoing calls. One call. I then enter sh call active voice command into the VG200.

Am I performng this correctly; on CallManager configuring VAD= True/False then making a call across the VG200 and type sh c

New Member

Re: Silence Suppression


I had the same problem with you before. Let me share to you some procedure that I did to elimanate that problem.

Now, don't change the settings of silence suppression under CCM. Always set it to false. On your voip dial-peer, configure it with "no vad". Also add this command in your voip dial-peer "incoming called-number ."

This will solve your problem. You can make an experiment with this. Try removing the "incoming called-number ." command in the voip dial-peer and then make an outside call then monitor it with show voice call summary. You will notice that the under enable vad column it will display "y" meaning vad is enabled. After that configure your voip dial-peer again with "incoming called number ." The make an outside call and perform same monitoring steps. You will notice that under enable vad column it will display "n" meaning your outgoing call is vad disabled.

Hope this will help.



New Member

Re: Silence Suppression

It is an issue of lacking comfort noise. So if A stops talking and B hears no noise in the background level, B thinks A is cut off but actually A is here. Check whether the comfort noise parm is enabled. Also I'm not sure whether 7960 and VG200 send SID to generate comfort noise. This is one direction you can look at.

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