Hum

I came across this excellent document written by it+46 on setting up an asterisk-based voice over IP (VoIP) telephony system.

The document is aimed at making it easy for communities in developing countries to put together cheap community-owned telephony infrastructure.

The first section of the document provides a very understandable overview of important telephony and VoIP concepts while the second part goes into detail about three simple scenarios with useful illustrations and configuration file extracts.

Using this document it looks pretty simple to put together a basic VoIP system with VoIP and traditional (TDM) phones connected to the public switched telephone network (PSTN) via a standard analog telephone line.