It seems, there is an issue with the buit-in SIP-Client and/or WiFi part.
All calls (incoming/outgoing) longer than 20-24 minutes resp. 21-24 MB transferred voice-data will be disconnected by the E90s/N95s.
We are using pcmu/pcma codecs, due to the excellent quality.
As soon we are changing the codecs to ilbc or g729, we can place calls with a longer duration.
We have checked that with several different gateways and providers, with the same result.
Who can confirm?
Any idea about a new firmware release solving the problem.