Ekiga is a nice linux voip program. Yet it has the limitation that its sound support does not understand .asoundrc devices. As a work around you can use an environment variable in .asoundrc to set the default device specially for ekiga.
But what if you want to have the ring sound on a different alsa device than the actual conversation? This is what I need with my DotAsoundrc, because my headphones are plugged in all the time. So I wrote a little python script, which uses dbus to connect to ekiga and plays the ring tone on a different device.