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New Member

CISCO UNITY - NOISE AFTER THE BIP

Hi,

We have the following scenario:

PSTN - PRI - AVAYA PBX - SIP TRUNK - CUBE - SIP TRUNK - CUCM - UNITY 7.0

When we call to the voicemail, after the "bip", we can hear a "sssssssh" sound. Have you ever experienced something similar? Can be related with the codec? It is strange, because the prompts and the "bip" are perfect, it is just the noise after that.

BRs!

4 REPLIES
Cisco Employee

Re: CISCO UNITY - NOISE AFTER THE BIP

Hello Alicia,

Yes it could be related to codec issue, Could you please check/confirm is any transcoding taking place? if any check which codec are being used with this command.

show dspfarm sessions

The problem arise only for said call flow scenario?

Br,

Nadeem Ahmed

Br, Nadeem Please rate all useful post.
New Member

Re: CISCO UNITY - NOISE AFTER THE BIP

Hi Alicia,

You mentioned the noise comes after  "bip" .

assumptions:

1. this is the "bip" which is played after Cisco Unity Connection asks you to record a message after "bip".

2. while Unity Connection plays Welcome message , there is no noise and clear message is heard.

Hence, the noise is heard after Cisco Unity Connection opens voice channel to receive your voice .

In that case , I assume this might be the CNG (comfort noise generation) or VAD (voice activity detection) issue.

It might be some kind of noise that is captured from your mic. and loopbacked to your phone speaker after being amplified.

I know my conclusion are long shots. But I wrote what came to my mind.

Kindly let me know your views on this.

Aman

--

“If you have knowledge, let others light their candles in it.”

“If you have knowledge, let others light their candles in it.”
New Member

Re: CISCO UNITY - NOISE AFTER THE BIP

Hi Aman,

Your assumptions are completely right. Do you know if I can check the VAD / CNG values in the Unity system (this is Unity, not Unity Connection, by the way)?

Thanks a lot!

New Member

Re: CISCO UNITY - NOISE AFTER THE BIP

Hi Alicia,

Here is a link I found for Changing VAD/CNG values in Unity:

http://www.cisco.com/en/US/docs/voice_ip_comm/unity/3x/troubleshooting/guide/313/TSG_0450.html#wp1078077

Here are some important Links related to VAD/CNG:

Unity Hissing sound:

http://www.cisco.com/en/US/products/sw/voicesw/ps2237/products_tech_note09186a00801663a2.shtml#dtmf

Hissing sound in call :

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a00800a9982.shtml#topic2

VAD/CNG:

https://supportforums.cisco.com/docs/DOC-2580

I never saw VAD/CNG issues , so kindly let me know if it worked.

Regards,

Aman

--

“If you have knowledge, let others light their candles in it.”

“If you have knowledge, let others light their candles in it.”
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