The alsachan module can be used either to test your Yate or to use Yate as a VoIP client with ALSA drivers.
From a routing module you can call the sound card like this.
The alsachan is intialized depending on what parameter you use to call it from the routing module. The default settings are what you are going to use in most cases.
To select a specific device you need to specify something like:
alsa/plughw:0,0 - please check the ALSA documentation on the naming conventions.
If you want to make your alsa the default in Yate client put in yate-qt4.conf: