This is the Title of the Book, eMatter Edition
Copyright © 2007 O’Reilly & Associates, Inc. All rights reserved.
Chapter 17: Asterisk Reference
Dialing/CallwaitCAS: 0/0
Default law: ulaw
Fax Handled: no
Pulse phone: no
Echo Cancellation: 128 taps, currently OFF
Actual Confinfo: Num/0, Mode/0x0000
There are many channel-specific settings, most of which are user-definable. You can
see from this list that, even within the scope of a single Zaptel channel, Asterisk is
extremely flexible. In our test server, this channel is an FXO channel—that is, a
channel that connects to the telephone company. In order to interact correctly with
the phone company’s switch, the X100P (or other compatible) interface has to use
FXS signaling, so that, to the phone company, it appears to be a regular telephone
answering the line and not a newfangled Asterisk server (FXO/FXS signaling was
introduced in Chapter 4). Other types of channels (SIP, H.323, etc.) have their own
channel-specific settings.
Inspecting the Dial-Plan
The show dialplan CLI command can be used two ways: showing the entire system-
wide dial-plan, or only showing a specific context or extension. Here’s the output for
a small, but complete, dial-plan:
pbx*CLI> show dialplan
[ Context 'default' created by 'pbx_config' ]
'3101' => 1. Dial(SIP/3101@ [pbx_config]
2. Voicemail(u4101) [pbx_config]
'3102' => 1. Dial(SIP/3102@ [pbx_config]
2. Voicemail(u4101) [pbx_config]
'3103' => 1. Dial(SIP/3103@ [pbx_config]
2. Voicemail(u4101) [pbx_config]
'8500' => 1. VoiceMailMain( ) [pbx_config]
'_9NXXXXXX' => 1. Dial(${PSTN}/{EXTEN:1}) [pbx_config]
2. Congestion( ) [pbx_config]
Ignore pattern => '9' [pbx_config]
[ Context 'incoming' created by 'pbx_config' ]
's' => 1. Answer( ) [pbx_config]
2. Dial(SIP/3103@|30) [pbx_config]
3. Voicemail(u4101) [pbx_config]
4. Hangup( ) [pbx_config]
In the default context, several extensions are configured to ring calls on specific SIP
telephones with static IP addresses and an extension pattern that matches outbound
calls. The 8500 extension is one that allows private users of the Asterisk system to
access the voice mail management greeting.

Get Switching to VoIP now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.