Stoter sound CP 7925

Unanswered Question
May 7th, 2009

I client of mine has bought 5 CP7925. After a lot of trouble adding them to the UC500 with 2 AIR-AP521G-E-K9 connected to it they're finally up and running.

The only trouble is that after a not measrable time frame they start to stoter sound. I'll even make it spookie, 2 CP7925 registerard to the same acces point 1 has stoter sound the other doesn't, SAME SETTINGS.. I'll even make it more spookie 2 other phones registard to anther acces point, one stoters the other one doesn't when i remove the battery of the one that stoters the problem is gone after a reboot, bud not with a simple reboot of the phone. (by power button)

Does anyone have an idea?

Note that after changing form WPA to WPA2 the time frame did expand and even the range expanded..!!



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hotrot_net Thu, 05/07/2009 - 23:54


These guidelines are just guidelines not a soluition to my problem.
Of course a followed the instructions provided by Cisco only 2 acces point on the UC500 without a 520 Wireless Express Mobility Controller.

The connection to the AP's is not the problem. The problem is that the phone's sometimes start to stoter, and after unplugging the battery the problem is gone, a simular phone on the same AP doesn't have that problem(at that time). But after a piriod of time the same problem starts again on one of the phone's (or both). The problem was even worse with WPA  (one) , after setting the AP to WPA2 the problem is as good as gone but never the less stil comes back now and then. The only way to resolve it is to unplug the battery of the phone that causes the problem. At that time te phone has a good wireless signal but stoters like hell.

So please don't answer it with a nice presentation of the cisco Wireless Express Mobility Controller.

I see now that in the 6th page your advice is that with 2 access points ONLY DATA is an option..!!! COME ON CISCO.. if that is what the new statement is form cisco then I never can sell it to SMB clients. After reading the paper that comes with the UC500 ( CIsco Smart Business Communicatinos System Setup ((version 1.0)  at page 7  a picture (number 230637) states other wise then provided in the presantion.

It would be a flaw if wireless Voice only can be made with a 526 ..!!! because a 526 here in the netherlands  costs € 826,-- that's almost as much as the whole UC500, that has the capability to provide the same as the 526. In the statement that is made in the presenstion, means that this client has to buy a 526 just for 3 wirless CP7925 ( wich also are not cheap..!!!!!) this puts the UC500 right of the marked for SMB.!!



Marcos Hernandez Mon, 05/11/2009 - 20:26

Hi Andy,

We can address the concerns about product positioning on a different thread or privately. Feel free to email me at [email protected]

Going back to your problem, I have been doing some research and I found a few similar instances. A couple recommendations to try before we send you to TAC:

1) Since you mention the battery, in at least one case changing the "on call power save" to "none" helped.

Settings -> Network Profiles -> Profile Number -> WLAN configuration
->Call Power Save Mode (press **#) and change it to NONE

2) Do you notice the stuttering when Music on Hold (MoH) is played? The AP521 has some performance limitations with regards to multicast. You can try changing to unicast MoH. Sample config below:

ephone-dn  9
number BCD no-reg primary
description MoH
moh ip port 2139 out-call ABC

After change
ephone-dn  9
number BCD no-reg primary
description MoH
moh out-call ABC



hotrot_net Mon, 05/11/2009 - 22:27

Dear Marcos,

Bin there don that. I've already tried the options you provided. It helps a litte. But still the problem returns

MoH is turned off on the CP7925's.. I do have the same trouble with the voice mail access. So it's got nothing to do with interconnect to other voice lines. I also installed the latetest firmware (1.3) on the phone's but that also didn't fix my problem.

Maybe this info will lead to another solution.



Marcos Hernandez Tue, 05/12/2009 - 19:18


I did find an internal request from someone who encountered THE EXACT SAME PROBLEM that you are seeing, but there's no follow up and the thread goes unanswered...

May I kindly ask you to open a TAC case and send me the number when you are done, so we can track it? This definitely looks like something on the product side and not related to your deployment.


Marcos Hernandez
Technical Marketing Engineer
Cisco Systems, Inc.

infoestrie Fri, 03/05/2010 - 20:43

Did you found a solution of your problem? I Have exactly the same problem.



hotrot_net Sat, 03/06/2010 - 01:46

Dear Daniel,

I did found the solution..!!! It's a cisco mis manufacturing. and they don't even give in to it.

After spending a lot of time (money) at a site where I had this trouble I finally got some one of the cisco Wirelless TAC team that helped me out.
The problem you have is the software on the phone..!!!! you have to contact cisco and ask for this file


Then all your troubles are over.

I spend over 7500 euro solving this trouble and the only thing cisco has to say on that......" we have a lot of 7925 phones that don’t cause this trouble and you're the first that has these troubles, we're not gonna help you out with whatever compensation."  in other words I spend a lot of money making it work and even though it's a cisco software related problem they not gonna compensate me in any way.

Never the less my troubles are over.


Andy Gribnau

UPDATE.. Cisco if you do read this please contact me again.. because it seams I'm not the only one having this problem!!!!

infoestrie Sat, 03/06/2010 - 06:53

Thank you very much for your reply.
I just have one last question
where I can download this file?
on site cisco there is only 1.3.3

Thank you in advance

hotrot_net Sun, 03/07/2010 - 02:05


I know that the file is not online..!! That is just what I’m complaining about.. Without this file its not working. YOu have to ask cisco about it.. Make a TAC and ask for the file..


Andy Gribnau

Steven Smith Mon, 03/08/2010 - 20:27

Looks like this issue is fixed in 1.3.4 firmware for the 7925 which went live on CCO today.  The bug id for this problem is...

CSCtc54410:  7925 has voice gaps for PSTN calls when connected to CME

I am working on getting this into the 8.0.2 software pack as well.

stacy.thompson Wed, 04/21/2010 - 09:51

We have 2 7925's on a UC560 with an ESW and an AP521G.

The 7925 users experience dropped calls frequently !?  They want to throw the phones out the window...

We have 1.3.4 firmware loaded, so now what ?

I'm not sure if I call TAC or STAC ?

SEP00269946B1EC   CP7925G-1.3.4          CP7925G-1.3.4          Initialized

SEP00269946C90D   CP7925G-1.3.4          CP7925G-1.3.4          TCP-timeout



hotrot_net Mon, 09/28/2009 - 08:37

Dear Jose,

Did every posible option NOTHING seems to help. After a while the whole thing starts again.

1. try 2 chang from wpa to wpa2 that might help.

2. when you want to use Bleutooth you have 2 use a Access Point that sends the SCCP protocol over wifi A like the Cisco Aironet Wireless Access Point 1131 otherwise it wont work.

3. a TAC case ??? Don't think that is gonna help.. why its a software issue on the phone's.

3 --> you would ask why do I come to that conclusion, simpel when removing the battery from the phone the probelms are solved. And dissapeers like rain.

I also tryied 2 use the new software 1.3.3 but that give's a mirror error on the phone's when installing.

I almost lost a client because of this.. I had 2 really argu a lot and give away hours of work..!



Marcos Hernandez Mon, 09/28/2009 - 13:37

Even if this is a software issue on the phone, a TAC case should be open so one of our engineers can contact development and get it fixed.


hotrot_net Mon, 09/28/2009 - 15:18


You have a point there. Bud never the less I repoted it here the 7th of MAY.. It is september already and the Cisco team didn't do anything. Can't tell me that where the only one that have these troubels

This is a support forum isn't it? wouldn't it be nice if someone like you would just walk over to the desginteam and gave them a notice.??

I can't even make a TAC because the waranty is lit... Only 3 months support on the phones or am I mistaking?

Marcos Hernandez Tue, 09/29/2009 - 05:22

I see what you mean, but the open issues in this forum are not meant to replace a TAC case and the support processes. Ocasionally, we will directly submit a bug report based on our findings here in the Support Community, but that is rare. The TAC case is the official, reliable way to proceed.

Thanks for your understanding.


hotrot_net Tue, 09/29/2009 - 07:08

Dear Marcos,

Still haven't an answer.. Can I still make a TAC case altough my waranty of 3 months has expired



Oh yes make a TAC..

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Steven Smith Tue, 09/29/2009 - 07:38

I have found a bug, but I am not sure it will fix the issue or not that you are seeing.

1-way audio due to no Networkdown event to SCCP when switch profiles

Looks like this is fixed in 1.3.2 and 1.3.3 firmware for the the 7925 phone.  Try upgrading to 1.3.3 and see if you have the problem.  Otherwise, you should probably open a TAC case.

hotrot_net Tue, 09/29/2009 - 07:42


The 1.3.2 is allready in use. The 1.3.3 won't install..! the phone answers with mirror not correct in the last % of the update.



hotrot_net Tue, 09/29/2009 - 08:15

Good to know it safe me to install 1.3.3.

And no not only 1 one audio also stoter sound.

hotrot_net Thu, 10/01/2009 - 11:12


Maybe some good news.. I told you early that the 7925 wont work with the AP521 and Bleutooth I gave you an alternative for that namely the

Cisco Aironet Wireless Access Point 1131

After placing a second AP1131 and setting the wifi to Radio 802.11A and setting the CP7925 to only 802.11A at the client that was having trouble, he told me today that his troubles are over.

That means that the AP521 and the CP7925 en CP7921 are not a good combination.

The phones are stil one 1.3.2 and te problem is gone.!!!

Can someone at cisco trade me in the AP521 for AP1131..!!!!



Hello Everybody,

Just wanted to share my 2 cents for what its worth.  I am working on a new deployment with 38 APs (1252s) and 40 some wireless phones of the type 7925.  In the beginning we used 1131 APs in a limited environment to give the users some wireless access.  We hardly heard of any issues.  Now that the 1252s have been deployed we hear about calls being dropped, phones deregistering/re-registering, and stutter sound.  The worst thing about this is that it even happens when users are stationary in a room with an AP in it.  So no roaming and other factors included.

I have two cases with Cisco open on this one.  One is with the voice team and one with the wireless team.  The wireless team is convinced that all settings on the wireless controller are correct (5500 controller).  The voice team is convinced that all settings in the PBX are correct (3845 CME running 7.1 code).  Yet, the problems are still there.  I have no issues with plugged in phones (7941s).

I found that sometimes factory defaulting the phones fixed the stutter problem but it never fixed the call dropping.  The 7925 phones were running 1.3.1 code and I just started to deploy 1.3.2 since Cisco TAC did not recommend 1.3.3.  But reading other users posts, I am not sure if this really fixes it.

I am really not happy with the performance of the 7925 at this point.  I am wondering if 7921's would work better.... Maybe Cisco will deliver another firmware soon that fixes this.


Steven DiStefano Tue, 09/29/2009 - 05:30

Having the post here is always a good idea and usually if you stumbled into an issue we are aware of, you get immediate assistance.  In some cases, we dont know about the issue, but having the post widens the audience to our Partner Community, and maybe they will respond with advise as well.  In some cases, the TAC case is required (if it smells like a bug).

Hi all,

The 7925 uses a high UDP+RTP port (>16384) to talk to other phone 7925 or 7940.
And I see that 7925 uses the port UDP port 2000 to RTP traffic, to talk to PSTN or CUE.

When 7925 uses the high port there isn't any problem, no voice stutter, and delay of ping about 20 ms.
When 7925 is ilde or uses the port 2000, there are problems, voice stutter, and ping's delay can reach 500 ms.

I thing that if i could change this UDP+RTP port for outsite calls I have resolved my problem.

Is there some parameter in Cisco Call Manager Express to change this value ?

Any idea about this?


BR // JI.

IOS CME: c2800nm-spservicesk9-mz.124-22.T1.bin
Firmware 7925: CP7925G-1.3.3
AP 1130, IOS: c1130-k9w7-mx.124-10b.JDA3

Marcos Hernandez Mon, 10/05/2009 - 13:24

Hi Jose,

Without a complex NAT configuration, this range cannot be altered.




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