Folks have so far logged over 4 million calls using Asterisk, but many more have used Vonage, 
Skype and others.  
Just so you know, the book isn't all about Asterisk. Chapter 16 is devoted to the latest list of 
Softphones, Instant Messaging Software, Desktop Telephony Software Developer Tools and 
SoftPBX systems, VoIP Service Providers and Telephony Hardware Vendors. The playing field 
has leveled off somewhat from when I did my thesis project on Internet Telephony for my 
Masters degree and many of the companies I knew and tested while working at TMC Labs 
) are still there. 
Ted does an excellent job showing how VoIP continues to become the  disruptive  technology 
that has changed the fortunes of the existing Bell Telephone companies around the world 
This is a book for telephony geeks (and I guess I'm in that category too). There are 17 chapters 
covering the differences between Voice and data, convergence, Linux as a PBX, circuit switched 
telephony, Enterprise applications, voice circuit and call signaling replacements, implementation 
plans, quality of service, security monitoring and troubleshooting tools, trunks and network 
infrastructure converged apps, problem situations, VoIP vendors and services and the Asterisk 
Reference. There are also 3 Appendices on SIP methods and responses, AGI commands and the 
Asterisk Manager socket API syntax.  
Are you interested in looking at both the strengths and current weaknesses of circuit and packet 
switched networks and how VoIP interacts with them? Interested in learning how VoIP is 
relatively secure, but want to know how to harden the SoftPBX server even further? Want to 
know how to configure IP phones or how to work with SIP and firewalls? Or bring together 
Email and Voicemail? How about understanding how VoIP plays with the OSI model and 
telephony call signaling standards? 
Ted Wallingford brings it all together in typical non boring O'Reilly fashion. Now I just have to 
figure out how to get the Asterisk Launcher to work properly under Tiger. By the way, the team 
at Astmasters are looking for more programming volunteers to help them make Asterisk play 
nicer with Mac OS X. 
  MPN, LLC 2005 macCompanion 
Page 51 
August 2005, Volume 3 Issue 8 

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