[cisco-voip] Cracking noise during calls

[Erick Wellnitz]

I ran into something similar many years back.

If G.729 is being used be sure VAD is turned off at the gateway.  I had an
issue once where we would get popping and crackling when VAD had engaged
then one party would begin speaking.  Another idea would be to check the
voice port settings to make sure echo cancellation is turned on.  I had an
issue recently where users reported crackling and the echo cancellation was
not configured.

Make sure you have QoS (probably not the issue) is configured for the
Ethernet interface of the gateway.

A packet capture on the gateway can be done using the following method to
see if anything seems off:  https://supportforums.cisco.com/docs/DOC-5799


On Fri, Oct 25, 2013 at 7:40 AM, costas georgiou <ckos1976 at hotmail.com>wrote:

> Hi All,
>
> Thanks for your comments.  The issue is still here.  Bear in mind the
> issue is external outgoing and Incoming, Internal calls are crystal clear.
> I have run a Sniffer from the back of the phone, when I check the RTP the
> source in the IP address of the gateway and the destination is a Multicast
> address?  When I play it back I get MoH.  I am trying to hear the numebr
> that I am dialling, so not sure if the sniffer is setup correctly.  On the
> otehr hand, I have check the controller e1 and there are no errors.  I have
> checked the statistics on the phone and there is no packet loss, however, I
> have seen Jitter go up to 80.  Also, I have run Show voice call active, and
> there have been no increment Late packets to suggest Jitter, no gaps in
> Silence increase to suggest Choppy Voice and no increase in Gap with
> Prediction to suggest Synthetic Voice.  I have replaced on phone that had
> the issue with a spare and the issue is still there and I have also moved
> them over to a new switch port.
>
> ANy ideas would be appreciated.
>
> Kind Regards
>
> Cos
>
>  ------------------------------
> From: mikenorton at pwsd76.ab.ca
> To: cisco-voip at puck.nether.net
> Date: Mon, 21 Oct 2013 15:26:37 +0000
> Subject: Re: [cisco-voip] Cracking noise during calls
>
>  I’d start with looking on the gateway for ISDN errors. “Show controllers
> t1” (or e1, depending on your country). If you are getting errors there,
> make sure your gateway is configured to use the carrier as its clock source.
>
>
>
> -mn
>
>
>
>
>
> *From:* cisco-voip [mailto:cisco-voip-bounces at puck.nether.net] *On Behalf
> Of *costas georgiou
> *Sent:* October-21-13 8:19 AM
> *To:* cisco-voip at puck.nether.net
> *Subject:* [cisco-voip] Cracking noise during calls
>
>
>
> Hi guys,
>
> I have an issue on one of my sites, where someone makes an outgoing call
> through the ISDN, they hear a crackling sound on the phone.  This is only
> happening to three phones out of 15.   The person on the other end cannot
> hear this, only the person who is making the call from the IP phone.  The
> provider apparently has checked the ISDN and all seems fine, the gateway
> has been completely replaced and also moved closer to the ISDN circuit.  We
> have swapped over a phone that we think did not have the issue, but it is
> still there.
>
> Any ideas?
>
> Thanks and Regards
>
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