7920 Wireless IP phone

Unanswered Question
Aug 15th, 2008

Hi All,

We have 7920 IP phone which works fine for the most part. It can correctly associate with the AP.

But the problem lies with the user not able to hear voice from the caller, while the caller can hear everything what the user is saying. Can anyone please tell me what and where the problem is?

will rate helpful posts. Thanks.

I have this problem too.
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Justin Brenton Fri, 08/15/2008 - 08:27

Hi njanardhan ,

Does this happen only with the Wireless IP Phone's?

Are you using QOS for these devices?

Audio Problems:

There are a few common configuration errors that can cause some easily resolved audio issues. If possible, check audio problems against a wired phone to help narrow the problem to a wireless issue. Common audio problems include:

•No audio

-A common reason for no audio is that TKIP and/or MIC are configured on the AP. These features are not yet available for the Cisco 7920 Wireless IP Phone and can cause audio issues if enabled.

•One-sided audio

-This problem can occur in the fringe areas of an AP, where a signal might be too weak on either the phone side or the AP side. Matching the power settings on the phone and the AP, when possible, can fix this problem. This problem is most common when the variation between the AP setting and the phone setting is large (for example, 100 mW on the AP and 20 mW on the phone).

-Check the gateway and IP routing for voice quality.

-Check to see if a firewall or NAT is in the path of the RTP packets. By default, firewalls and NATs cause one-way audio or no audio. Cisco IOS and PIX NATs and firewalls have the ability to modify those connections so that two-way audio can flow.

-One-way audio can occur if ARP caching is not configured on the AP. Refer to the section on AP Configuration (for Installation), for information on how to set this feature.

•Data rate settings

-If there is a specific data rate set on the phone or AP, then they must match or the phone must be set to its default of automatic.

•Hardware issues

-To make sure the speaker is functioning properly, first check the volume settings under the selected profile, then enable keypad tones to check the speaker.

-For additional speaker issues, refer to Field Notice 29257, available at


•Ring volume too low

-Louder ring tones (such as loudlaser.raw) are available on Cisco.com. Loud ring tone must be downloaded via TFTP with Cisco CallManager and not with the Configuration Utility.

From this doc


Hope this helps, Please rate if so



Naveen Raj Janardhan Fri, 08/15/2008 - 08:39

Thanks justin for a very detailed response:)

What I forgot to mention in my earlier post was that, this phone was working absolutely fine until yesterday...also, there were no changes made to the AP or any of the switches.

Is it possible that the 7920 has gone bad?


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