congratulation! ZoiPer is a fine piece of software. I like it. Today I was able to configure ZoiPer on iOS 7.1.2 (iPhone 4) to a AVM router 7490 (latest OS: 06.51). I still bought also the additional audio and video codecs for ZoiPer.
I played around with audio codecs. I disabled one after another, until only G.729 was switched on, which I'd like to prefer. Athough the AVM router 7490 shall support G.729 (it is there called G.729a see: http://en.avm.de/service/fritzbox/fritzbox-7490/knowledge-base/publication/show/1008_Voice-codecs-for-Internet-telephony-supported-by-FRITZ-Box/ ) ZoiPer fails when trying to dial. Error message: Not Accacceptable Here (488).
Is it possible to fix this non-compatibility by ZoiPer?
Thank you for looking onto this matter.