Vipa is software made in XL programming language made for annoying users via trying to establish data call to their cell phone. Actually users can't accept call. So if you call them again and again victims will become really nervous.
This document and source code included in it is just proof of concept, nothing more, nothing less. Author of this document is not responsible for any damage made using this document etc.
If you do want to set up XL and run the script called Vipa, which offers you calling and annoying people without minicom and detecting if they are unreachable or something else use Vipa.xl. First you need to setup XL interpreter on your Linux. Go to http://trac.m3w.org
to know how to do that.