The “VoIP-4D Primer” is a free guide available in four major languages. The work is an effort to disseminate the use of telephony over the Internet in developing regions.

The 40-page guide targets both technical and non-technical readers. The first part presents the essentials of telephony over the Internet.

For those interested in the more technical details, hands-on guidelines and configuration files are included in the second part. The examples provide essential background to build your own low-cost telephony system.

English Version:
http://www.it46.se/downloads/voip4d/en_voip4d_it46_release_web.pdf
Arabic Version:
http://www.it46.se/downloads/voip4d/ar_voip4d_it46_release_web.pdf

The website URL is: http://www.it46.se/voip4d/voip4d.php?lang=en

The guide uses the popular open source system named Asterisk.