I'm sorry if I ask you the same thing but I have to summarize your
problem.
All computers can successfully make test calls. Right?
Can you hear the woman when test call begins?
If you try from Ubuntu distro to contact into your sister, all you can
hear is your voice from your speakers?
Does the same problem is for windows too?
If you hear your voice, then you (probably) must configure the
input-output settings.
Or the 'Audio - Devices' from the 'preferences'