Avaya IP Office Bad Voice quality with Xperia SIP Native client

[LPS-Defence]

Hi all,

We are using Xperia x phones as SIP phones in an IP Office V2 (version 9.0)environment.
Sip client is Xperia native Sip client.

We got a very bad voice quality, particularly SIP to SIP.
Any recommendation? Do you have any experience with Xperia SIP client?
Do you have better result with other SIP applications?
Do any IP Office parameter need to be adapted (codec used are G729 and G729)?
What about Qos?

Thanks a lot for your help.

 

[janni78]

Is it over mobile connection or WiFi?

"Trying is the first step to failure..." - Homer