This is a method of providing a phone service to people over the Internet. This type of service moves the traditional phone switch off site and allows more than one company to use a particular switch.
The basic idea behind a Call Shop business is to have a place where customers can make local, long distance or international phone calls. The main sources of revenues will come from the minutes customers are going to spend on the phone. So it all depends on the rates that you are going to setup, just make sure that they are lower than the ones offered by the providers of international call services.