Calling cards biz

Hi everybody!
And for my first question after registration :smile:
I am seeing a good opportunity to develop a calling cards business in the developing countries.
I am only briefly familiar with VOIP technology and from what i’ve gathered so far i understand that to make a calling cards voip service all i need is :

  1. A termination service
  2. Asterisk with a2billing
  3. A T1 phone line in order to allow the callers to access my servers
  4. A wide i-net connection to facilitate the VOIP traffic.
    and ofcourse machines to run the software.

Am i wrong ? Am i on the right path ?

Thanks !