This article was originally published in September, 2009.

FreePBX 2.5 Powerful Telephony Solutions by Alex Robar (Packt Publishing) explains how to set up, configure, and maintain a powerful VoIP PBX using FreePBX.  For those not familiar with FreePBX, it’s a “front end” for the Asterisk PBX software. Asterisk can be thought of as the “engine” that runs the PBX, but FreePBX is the user interface.  It basically saves you the effort of writing Asterisk configuration files and dial plans by hand.  Instead, you enter all the requisite information in FreePBX’s web-based GUI, and then when you apply the configuration changes (by clicking an orange bar at the top of the screen), FreePBX (re)writes the Asterisk dial plan and configuration files on the fly. This means that making significant changes to the call flow within the PBX, or adding new extensions or trunks, can be accomplished in a matter of seconds or minutes. It also means that you can have a fully functional PBX up and running in a few hours (perhaps even less than an hour if you’re exceptionally quick and it’s not your first installation).

As I like to do in reviews, before I begin I’ll give you a thumbnail description of what’s in each chapter (condensed from information on the Packt Publishing web site):

• Chapter 1: Installing FreePBX – Installing FreePBX on CentOS 5.2 or Ubuntu Server 8.10
• Chapter 2: Module Maintenance – how to install and update modules
• Chapter 3: Devices and Extensions – explains the difference between Extensions mode and DeviceAndUser mode, and explains how to set up extensions and users. Also explains the different types of endpoints, and how to set up voicemail for a user or extension
• Chapter 4: Trunks – discusses trunk types, setting up a new trunk, and checking trunk status
• Chapter 5: Basic Call Targets – explains various ways to terminate calls on a FreePBX system, including Extension and Voicemail, Ring Groups, Conferences, Day Night Mode, and Phonebook Directory
• Chapter 6: Advanced Call Targets – discusses Queues, Time conditions, and the setup of an IVR (Digital Receptionist)
• Chapter 7: Call Routing – discusses Inbound routing, Follow Me and the VmX Locater, and Outbound routing and Least Cost Routing
• Chapter 8: Recording Calls – focuses on everything you need to know about recording calls that pass through a FreePBX system
• Chapter 9: Personalizing Your PBX – discusses Custom Music on Hold, Custom voice prompts, Directory search options, Customizing feature codes, Callback, Direct Inward System Access (DISA), CallerID Lookup Sources, PIN Sets, Misc applications, and Misc Destinations
• Chapter 10: System Protection, Backup and Restoration – how to protect your system against failure, discussing both hardware methods (a good UPS and redundancy) and backups and restoration
• Chapter 11: Security and Access Control – explains how to upgrade your operating system and Asterisk, plus various ways to secure your system against attacks

There are also four appendices:

• Appendix A: FreePBX Modules
• Appendix B: Feature Codes
• Appendix C: Voicemail.conf Options
• Appendix D: Common Trunk Configurations

I’m coming from a slightly different place in my review of this book than with other books I’ve reviewed. In this case I’ve already very familiar with the subject material, having helped set up and configure a FreePBX system that belongs to another member of my family. I was a bit afraid that because I’m already so familiar with the subject, I’d find several glaring errors or oversights. Happily, that proved not to be the case – this book is a good, solid treatment of setting up and configuring a FreePBX system. In fact, the title should have been “How to set up and maintain a FreePBX system”, because that’s exactly what this book explains.

The first thing that impressed me about this book is that there was no “filler” material. Very often, with technical books, the author really only has about 75 to 100 pages of actual material, but because publishers like to publish books that have somewhere around a couple hundred pages, the author will flesh out the book with a history of the software, a profile of the developers, comparisons with competing products, and (if they are really desperate for material) a history of the Internet. 🙂 That is not the case here. After a very short preface, the author jumps right into the subject material, starting with how to install FreePBX and then continuing through subsequent chapters with virtually everything you need to know about configuration. While not every chapter may be meaningful to every reader (personally, I’ve never had the need to record a call — so far — but it’s nice to know that FreePBX can do it), the book at least touches on all the major features of FreePBX.

If I had to make one criticism of the book, it’s that in some places it reads a little bit too much like an instruction manual. And that’s not necessarily a bad thing, because FreePBX has badly needed a good manual to assist first time users in getting it set up and running. This is the manual that should have come with FreePBX. That said, the author really doesn’t touch some of the problems frequently encountered by new users. For example, in the discussion of SIP endpoints, he notes that “SIP can be problematic when traversing firewalls and other NAT devices” and that “Configuration can be particularly troublesome if both the endpoint and the FreePBX system are behind their own firewalls” (p. 44). And there he leaves the reader hanging. There is no discussion of how to overcome the problem, nor is there a pointer to the FreePBX FAQ’s or How-To’s anywhere in the book. While many readers may not encounter this issue, a fair number will, and it would have been nice if they’d been thrown a bone, if only in the form of a pointer to the FreePBX page that addresses the issue.

In my opinion, perhaps the biggest omission is in the discussion of Trunk setup in Chapter 4. This was really the only chapter in which I got the distinct feeling that the author may have been in just a bit over his head, and perhaps did not fully grasp the subject matter covered in the chapter. Not only are there errors in his examples of dial pattern usage (p. 81 – under no circumstances would you use two pipe characters in the same dial pattern, as is shown for some of the toll-free number examples), but when discussing IAX2 and SIP trunks (p. 83), only cursory information is given about how to populate the PEER details and USER details fields. Nor is it explained that with many commercial VoIP providers, the USER context and USER details fields are not used, and should be left blank. However, in the author’s defense, I suspect that I understand why this may have happened — there probably aren’t ten people on the face of the earth that can give you a full explanation of all the options that could possibly be used in the trunk PEER and USER details fields, and when and how each option should be used. Trunk configuration is probably the most difficult part of setting up FreePBX, precisely because there’s no definitive guide on how to do it correctly. In most cases, I suspect that finding the correct options to use with any particular provider is a matter of trial and error — you make educated guesses about which options might be needed and how they should be configured, and if you find a combination that works, perhaps you post it so that others can use it. Some of the known working trunk configuration settings appear in Appendix D of the book, but there are more sample configurations available at the FreePBX web site.

I only mention this because I was hopeful that maybe someone would finally provide a really good how-to on setting up FreePBX trunks, since this is something that almost always confounds new users, and even causes experienced users to get a few (more) gray hairs on occasion. Had I been writing such a book, and had I really understood the subject, I might have given several pages to the subject of trunk configuration in general, and PEER and USER details in particular, not just a few cursory paragraphs. On the other hand, most users will probably seek out a tested and working trunk configuration for whatever provider(s) they use.  It’s not as though there isn’t any online help on the subject, but — and this is another minor criticism — for some reason the book barely mentions the availability of online help (for example, unless I missed it there is no specific mention of the FreePBX How-Tos that address several of the issues encountered by new users). This is why I say that at times the book reads like an instruction manual — it gives you all the basics, but seldom touches the “edge cases”, the little quirks and problems that may be encountered by a significant subset of users, but not by all.

However, I don’t want to leave you with the idea that this book is simply a rehash of information that could be found online — even if that were the case, it presents that information in a logical manner that is easily understandable by the reader. But, many essential functions of maintaining a FreePBX system happen outside of the FreePBX interface. For example, you cannot update your operating system or Asterisk from within the FreePBX GUI, but the book explains how to do both.  Chapters 10 and 11 (on System Protection, Backup and Restoration, and Security and Access Control) deal with functions that are at least partially handled outside of FreePBX.  In some instances the author provides useful shell scripts that automate particular tasks (for example, deleting old, outdated backups to avoid filling up the hard drive). And in many cases, the book does explain things that new users need to know, but might not know that they need to know — for example, the explanation of Codecs and the penalty involved (both in terms of system performance and call latency) in transcoding between codecs.

Anyway, the bottom line is this: Let’s say your boss wants you to set up a new office phone system using Asterisk, and gives you a couple of weeks to do it. If you have no prior experience with Asterisk, you will almost certainly want to use FreePBX (the alternative is writing dial plans and configuration files by hand, and trust me, you don’t want to do that unless you are the sort of person who enjoys writing source code for major projects, and even then you probably don’t want to do it if you’re under any sort of time deadline). And if you’re going to use FreePBX, and you don’t want to spend hours and even days ferreting out information on the Internet, you need this book. Get your boss to buy it (there’s even an e-book version if you need it right now), then just follow the instructions, chapter by chapter. In a few days time, you’ll be well on your way to becoming a FreePBX expert.  That’s partly because FreePBX is so easy to use in the first place, but also because the book tells you pretty much everything you need to know, in a very understandable manner. If you get stuck, help is available at the FreePBX web site and at other various locations on the Internet.

If you are a long-time FreePBX user, you may find that you already know much of what’s in this book, but then again it might surprise you how much can still be learned.  For example, I found several good suggestions for adding additional security to a FreePBX system in Chapter 11 of the book — and let’s face it, many of us are probably a bit lax about securing our systems to the greatest possible extent (and that could be a very costly mistake).

One other point I should make — as the title of the book implies, it deals with a particular version of FreePBX, namely version 2.5.  Of course, as so often happens with a book about software, the ink is barely dry on the paper when a new version comes out.  FreePBX 2.6 has already been offered as a release candidate, and beta versions of FreePBX 3.0 are being made available.  From a user’s standpoint, version 2.6 will be nearly identical to 2.5 – there may be a few added options and such, but for the most part they are not things that you would need to worry about, or that would detract from the accuracy of this book.  However, FreePBX 3.0 will be a major rewrite, but it’s only available in an early beta version, and unless you are an experimenter that wants to be on the bleeding edge, you don’t want it yet.  Whenever you do move to FreePBX version 3.0 — and I’d be very surprised if a full release version is much closer than a year away — much of what you’ve learned about FreePBX 2.5 and subsequent versions will still be applicable (and also, I suspect that people will be using FreePBX 2.x versions for quite some time to come).

FreePBX 2.5 Powerful Telephony Solutions by Alex Robar (Amazon affiliate link)