1 The Asterisk Open Source PBX
2 by Mark Spencer <markster@digium.com>
3 Copyright (C) 2001-2005 Digium, Inc.
4 ================================================================
6 It is imperative that you read and fully understand the contents of
7 the SECURITY file before you attempt to configure an Asterisk server.
10 Asterisk is an Open Source PBX and telephony toolkit. It is, in a
11 sense, middleware between Internet and telephony channels on the bottom,
12 and Internet and telephony applications at the top. For more information
13 on the project itself, please visit the Asterisk home page at:
15 http://www.asterisk.org
17 In addition you'll find lots of information compiled by the Asterisk
18 community on this Wiki:
20 http://www.voip-info.org/wiki-Asterisk
23 Asterisk is distributed under GNU General Public License and is also
24 available under alternative licenses negotiated directly with Digium, Inc.
25 If you obtained Asterisk under the GPL, then the GPL applies to all
26 loadable modules used on your system as well, except as defined below.
28 Digium, Inc. (formerly Linux Support Services) retains copyright and/or a
29 sufficient license to all components of the core Asterisk system, and therefore
30 can grant, at its sole discretion, the ability for companies, individuals, or
31 organizations to create proprietary or Open Source (but non-GPL'd) modules
32 which may be dynamically linked at runtime with the portions of Asterisk which
33 fall under our copyright/license umbrella, or are distributed under more
34 flexible licenses than GPL.
36 If you wish to use our code in other GPL programs, don't worry -- there
37 is no requirement that you provide the same exception in your GPL'd
38 products (although if you've written a module for Asterisk we would
39 strongly encourage you to make the same exception that we do).
41 Specific permission is also granted to OpenSSL and OpenH323 to link with
44 If you have any questions, whatsoever, regarding our licensing policy,
47 Modules that are GPL-licensed and not available under Digium's
48 licensing scheme are added to the Asterisk-addons CVS module.
53 The Asterisk Open Source PBX is developed and tested primarily on the
54 GNU/Linux operating system, and is supported on every major GNU/Linux
58 Asterisk has also been 'ported' and reportedly runs properly on other
59 operating systems as well, including Sun Solaris, Apple's Mac OS X, and
64 First, be sure you've got supported hardware (but note that you don't need
65 ANY special hardware, not even a soundcard) to install and run Asterisk.
67 Supported telephony hardware includes:
69 * All Wildcard (tm) products from Digium (www.digium.com)
70 * QuickNet Internet PhoneJack and LineJack (http://www.quicknet.net)
71 * any full duplex sound card supported by ALSA or OSS
72 * ISDN4Linux compatible ISDN card
73 * VoiceTronix OpenLine products
75 Hint: CAPI compatible ISDN cards can be run using the add-on channel chan_capi.
77 Second, ensure that your system contains a compatible compiler and development
78 libraries. Asterisk requires either the GNU Compiler Collection (GCC) version
79 3.0 or higher, or a compiler that supports the C99 specification and some of
80 the gcc language extensions. In addition, your system needs to have the C
81 library headers available, and the headers and libraries for OpenSSL and zlib.
82 On many distributions, these files are installed by packages with names like
83 'libc-devel', 'openssl-devel' and 'zlib-devel' or similar.
89 Assuming the build completes successfully:
93 Each time you update or checkout from CVS, you are strongly encouraged
94 to ensure all previous object files are removed to avoid internal
95 inconsistency in Asterisk. Normally, this is automatically done with
96 the presence of the file .cleancount, which increments each time a 'make clean'
97 is required, and the file .lastclean, which contains the last .cleancount used.
99 If this is your first time working with Asterisk, you may wish to install
100 the sample PBX, with demonstration extensions, etc. If so, run:
104 Doing so will overwrite any existing config files you have. If you are lacking a
105 soundcard you won't be able to use the DIAL command on the console, though.
107 Finally, you can launch Asterisk with:
111 You'll see a bunch of verbose messages fly by your screen as Asterisk
112 initializes (that's the "very very verbose" mode). When it's ready, if
113 you specified the "c" then you'll get a command line console, that looks
118 You can type "help" at any time to get help with the system. For help
119 with a specific command, type "help <command>". To start the PBX using
120 your sound card, you can type "dial" to dial the PBX. Then you can use
121 "answer", "hangup", and "dial" to simulate the actions of a telephone.
122 Remember that if you don't have a full duplex sound card (and Asterisk
123 will tell you somewhere in its verbose messages if you do/don't) then it
124 won't work right (not yet).
126 Feel free to look over the configuration files in /etc/asterisk, where
127 you'll find a lot of information about what you can do with Asterisk.
129 * ABOUT CONFIGURATION FILES
131 All Asterisk configuration files share a common format. Comments are
132 delimited by ';' (since '#' of course, being a DTMF digit, may occur in
133 many places). A configuration file is divided into sections whose names
134 appear in []'s. Each section typically contains two types of statements,
135 those of the form 'variable = value', and those of the form 'object =>
136 parameters'. Internally the use of '=' and '=>' is exactly the same, so
137 they're used only to help make the configuration file easier to
138 understand, and do not affect how it is actually parsed.
140 Entries of the form 'variable=value' set the value of some parameter in
141 asterisk. For example, in zapata.conf, one might specify:
145 in order to indicate to Asterisk that the switch they are connecting to is
146 of the type "national". In general, the parameter will apply to
147 instantiations which occur below its specification. For example, if the
148 configuration file read:
150 switchtype = national
156 the "national" switchtype would be applied to channels one through
157 four and channels 10 through 12, whereas the "dms100" switchtype would
158 apply to channels 25 through 47.
160 The "object => parameters" instantiates an object with the given
161 parameters. For example, the line "channel => 25-47" creates objects for
162 the channels 25 through 47 of the card, obtaining the settings
163 from the variables specified above.
165 * SPECIAL NOTE ON TIME
167 Those using SIP phones should be aware the Asterisk is sensitive to large
168 jumps in time. Those who live in areas that are on Daylight Savings Time (or
169 equivalent) should set their system and hardware clocks to use UTC in order
170 to avoid any possible jumps in system time. There should be no noticeable
171 effects to the user, as you should still set your system to use the local
174 Even for those who don't live in DST zones, this issue may manifest itself
175 if the administrator makes large manual time adjustments. Thus, it is good
176 practice to keep the time on your Asterisk server synced to a reliable
177 source, such as an NTP server.
179 Also note that this issue is separate from the clocking of TDM channels, and
180 is known to at least affect SIP registrations.
184 See the doc directory for more documentation.
186 Finally, you may wish to visit the web site and join the mailing list if
187 you're interested in getting more information.
189 http://www.asterisk.org/index.php?menu=support
191 Welcome to the growing worldwide community of Asterisk users!