Call disconnects when phone is picked up

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Aug 1st, 2008
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Hi experts,

I am bit new to IP telephony world; we have one HKG remote location where the site has ccm 6.0. When we call from US location to HKG site the phone rings and call get disconnected as soon as it is picked up. As per basics it looks codec mismatch issue.

When we place from US location the traffic payload is on G.729 which is somehow not negotiated by HKG end phone device (7975G). I checked the HKG call manager regions which are attached. Please shed some light where the is in regions or it is lack /mis configuration of Transcoding in call manager.



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Overall Rating: 3 (1 ratings)
espereir Mon, 08/04/2008 - 02:27
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Have you tried to disable the G.722 codec on the 7975? The new Cisco phones support G.722 and try to use this codec whenever it is possible; please try to set to FALSE the Advertise G.722 codec parameter on both IP Phones and try the call again. If it fails again, would be possible to get a trace file of the failed call?


hclvoice Thu, 08/07/2008 - 08:07
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thanks you very much ! i will try disabling the G.722 codec advertiseing on IP phone configuration.

avdberg Tue, 08/12/2008 - 01:56
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We tried this with CUCM 6.1 at HQ and CCME at Branche and have the same problem. Phone at Branche rings and when picked up it's disconnected.

We are using 7911G en 7961G phone at both locations.

redrobish Sun, 09/14/2008 - 22:14
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It's definitely a codec mismatch.

1. have you tried setting a different regions for each remote location?

2. have you set the the Ip phone's setting to use that region?

We have the same issue but after setting up these two, it's fixed.

Hope that helps...

j.sillers Thu, 10/02/2008 - 15:20
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Thanks for the tip on the G.722

We moved all the phones from DP a to DP b and then outbound calling stopped working. We had to check the gateway checkbox for "Media Termination Point" so it would go up and use UCM MTP's and not the local gateway. While troubleshooting we saw the G.722 when we knew it should have been using G.711. That lead us here. Apparently we must have upgraded the phone load and enabled G.722 without realizing it but our GW IOS is too old to handle it.

We shut off the G.722 on the phones and everything is back to normal....of course tomorrow the users that call IP to IP a lot will complain about degraded sound quality with G711 but they'll have to wait until we can upgrade the GW.


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