After one minute on a VoIP call over wi-fi, the sound starts breaking up.
Pushing on a button returns the sound quality to normal (no break-ups) as it -- apparently -- removes the phone from some sort of power saving mode.
The call quality is maintained indefinitely if we set the "Power saving" (U-APSD?) option to "Disabled" (in Tools -> Settings -> Connection -> Wireless LAN -> Options -> Advanced settings).
Permanently disabling the "power save" mode does not seem something sensible to do considering how much data usage the phone is put through.
How do we fix this? How can we keep the sound from breaking up and, at the same, allow the "power save" mode to remain active for data usage?
We're seeing this on an N79-1 firmware v. 20.175 using the integrated SIP client.
Any help is very much appreciated.