1. OPEN SOURCE TELEPHONY
SYSTEMS

2. BASIC CONCEPTS... Session Initiation Protocol (SIP)
Voice over Internet Protocol (VoIP)
Virtual PBX
Softphones
Diagram Credits: Cisco.com

3. REPRESENTATIVE TECHNOLOGIES...
1. ASTERISK: Open Source Software for Custom Communications
Diagram Credits: Alta3Research

4. REPRESENTATIVE TECHNOLOGIES...
… Upgrading From Legacy Phone System
Diagram Credits: Alta3Research

5. REPRESENTATIVE TECHNOLOGIES...
Open Source Software for Custom Communications
2. ELASTIX / FreePBX
“Designing a good phone system that provides a rich environment for the end users means obtaining a solid understanding of tightly integrating the phones into the PBX
strategy.”

6. REPRESENTATIVE TECHNOLOGIES...
3. KAMAILIO: Open Source SIP Server

7. The Village Telco Project
Bo Kaap – Cape Town SA

8.  PSTN Wireless Project Supervisor: Professor Michael Adeyeye
SIP Server
PSTN
HTML 5
PHP Script
Mesh Potato 
VM1
VM2
Ubuntu Server
LAMP Server
CentOs Server
Elastix
AsteriskNow
Mesh Potato