An OTP application
I have asterisk (PBX) started on my PC and two users - 1001 and 1002.
So, that application doing simple thing: registered like user 1002 (using nksip) and send invite to user 1001.
Thats all. Just for test!
Use rebar3:
$ rebar3 get_deps
$ rebar3 compile
$ rebar3 shell