hi,

first of all, I solved the issue with ALSA permissions: by default,
/dev/snd/* devices are writable by "audio" group, but FreeSWITCH is
launched with "-g freeswitch" by default, and that excludes the
"audio" group from the list of active GID's. As a result,
mod_portaudio cannot find any audio devices.

A file "/etc/udev/rules.d/99-freeswitchaudio.rules" with contents:

SUBSYSTEM=="sound", GROUP="freeswitch"

sets all sound devices to freeswitch group. If it's an appliance that
is not supposed to run desktop applications, this method is the least
intrusive. Otherwise, you would have to mangle the systemd unit files,
to remove the -g option from exec string.

But now I have a strange issue, described here, with an audio attachment:
https://freeswitch.org/jira/browse/FS-10809

The hardware platform is PCengines APU2, running Debian Jessie:
http://pcengines.ch/apu2.htm
It has a USB 3.0 host which is otherwise working fine.

Any hints will be appreciated.