Asterisk Guide: How to Install Asterisk (Part 2 of 2)
Last week we discussed some of the less effective routes for Asterisk help and documentation. This week, I’d like to direct you to some of the more efficient ways to attain information on the subject.
An Asterisk Reference Model
“So what am I supposed to do” you ask? I’ve found that the developers at Digium working so diligently on the Asterisk code base are actually very good at keeping documentation. What I didn’t know, was that they only seem to keep that documentation in the source releases. To make sure you’re doing things correctly for YOUR version (I’m assuming 1.6+ but this should suffice for other versions as well) do the following :
- Download the source tarball for YOUR version
- Uncompress it
- Go to the “configs” directory
- Read every single file here
- Eat some pie (This is an important step)
This accomplishes three things:
• You now have a sample of *nearly* every config file that Asterisk needs to run. These can be dropped into your /etc/asterisk directory as they are, and it will help you go a LONG way in getting things setup.
• These files are immensely commented with helpful hints and usage examples for all of the things you need.
• You have a belly full of pie.
“But I don’t WANT to comb through all these configuration files to try and figure out what I need and what I don’t. Can you help me cheat a little?” Some files are definitely more important than others. Pay special attention to the following:
• extensions.conf – The brain of your PBX. This determines how calls are routed.
• sip.conf – This is where you configure your phones
• voicemail.conf – Pretty obvious
• meetme.conf – Virtual conference rooms
• queues.conf – Call queues
The rest of the files really depend on a couple of variables. First, it’s important to know the basic pieces involved in setting up a fully functional PBX.
• The Asterisk source code
• Zaptel or DAHDI source that matches your Asterisk version
- Asterisk 1.4.22+ will use DAHDI instead of Zaptel
• If you’re using them, the drivers for your telephony gateway device (PRI card, analog card)
- It should be noted that Zaptel/DAHDI contain the drivers for any Digium based cards.
Zaptel and DAHDI have their own configuration files and you’ll need to understand them as well. Typically, there are helper tools designed to create these files for you, but that often depends on the type of hardware and drivers that you’re using.
The Zaptel files are:
• /etc/zaptel.conf
• /etc/asterisk/zapata.conf
While the latest versions (1.4.22+) will use the DAHDI naming scheme instead:
• /etc/dahdi/system.conf
• /etc/asterisk/chan_dahdi.conf
That should go a long way in getting you started. I realize I didn’t give specifics (as I said I wouldn’t be earlier) but in my opinion, just diving into a working system will still leave you feeling overwhelmed when it comes time to actually configure a dialplan. If a straight walkthrough is what you want, those are available via Google.
Of course, if all of this seems too daunting a task for the time you have, there are companies who specialize in Asterisk based phone systems. Using Asterisk allows them (and us) to provide a lower cost solution with a lot of the same bells and whistles as the larger vendors.
Michael McNeil has been working with Voice Over IP technologies since February 2006 with Dalcon Communication Systems. He specializes in Asterisk: The Open Source PBX, Linux, and Perl development with a short background in Network Security.
