Re: Voice calls over Virtual Um

Hello Andreas, sorry for late response. First of all, it should be noted that voice support in OsmocomBB is experimental and undocumented. I have been working on GAPK back-end integration, and it seems you've already found some branch, but I would recommend to use 'fixeria/audio' instead of 'fixeria/mncc'. Please check out the configuration examples [1] for mobile app. There you should find the new 'audio' section, where: io-target hardware means that audio I/O (by default) should be handled by the hardware (i.e. by Calypso phone). GAPK is not enabled by default. In order to use GAPK based back-end, use 'gapk': io-target gapk It probably makes sense to rename 'gapk' to 'alsa', because at the moment 'gapk' enables both voice playback and capture using the audio system of the host that running mobile. This can also be configured: io-target socket In this case GAPK is not used, and all TCH frames are being forwarded to the MNCC handler 'as-is'. See [2] commit description for details. Please also note that audio I/O target != MNCC handler, that actually implements the Call Control logic. See [3] for details. [1] https://git.osmocom.org/osmocom-bb/tree/doc/examples/mobile/default.cfg?h=f… [2] https://git.osmocom.org/osmocom-bb/commit/?h=fixeria/audio&id=bdb285450… [3] https://git.osmocom.org/osmocom-bb/commit/?h=fixeria/audio&id=22edbf3f8… With best regards, Vadim Yanitskiy.