I had a few issues following the Debian "first steps" on Mint 17.3. Some issues were definitely specific to Mint 17.3, others probably apply elsewhere as well.
Firstly after the apt-get install, the guide suggests that Freeswitch should be up and running. It wasn't.
Attempting to start Freeswitch from the command line I got an error telling me Freeswitch wasn't configured and suggesting a command to copy the vanilla configuration. Unfortunately the suggested command only works if the /etc/freeswitch directory doesn't exist, but it did exist and instead of creating a copy of the vanilla configuration in /etc/freeswitch, it created a /etc/freeswitch/vanilla subdirectory and Freeswitch still wouldn't start.
There don't seem to be any suggested softphones for Linux. It seemed likely that linphone would run in Linux, however the version of linphone that is provided in the Mint 17.3 repositories has a known bug and the current version, installed from PPA crashes when I try to dial.