Asterisk: The Future of Telephony

Table of Contents

Copyright

Foreword

Preface

Audience

Organization

Software

Conventions Used in This Book

Using Code Examples

Safari® Enabled

How to Contact Us

Acknowledgments

Chapter 1.  A Telephony Revolution

Section 1.1.  VoIP: Bridging the Gap Between Traditional Telephony and Network Telephony

Section 1.2.  Massive Change Requires Flexible Technology

Section 1.3.  Asterisk: The Hacker's PBX

Section 1.4.  Asterisk: The Professional's PBX

Section 1.5.  The Asterisk Community

Section 1.6.  The Business Case

Section 1.7.  This Book

Chapter 2.  Preparing a System for Asterisk

Section 2.1.  Server Hardware Selection

Section 2.2.  Environment

Section 2.3.  Telephony Hardware

Section 2.4.  Types of Phone

Section 2.5.  Linux Considerations

Section 2.6.  Conclusion

Chapter 3.  Installing Asterisk

Section 3.1.  What Packages Do I Need?

Section 3.2.  Obtaining the Source Code

Section 3.3.  Compiling Zaptel

Section 3.4.  Compiling libpri

Section 3.5.  Compiling Asterisk

Section 3.6.  Installing Additional Prompts

Section 3.7.  Updating Your Source Code

Section 3.8.  Common Compiling Issues

Section 3.9.  Loading Zaptel Modules

Section 3.10.  Loading libpri

Section 3.11.  Loading Asterisk

Section 3.12.  Directories Used by Asterisk

Section 3.13.  Conclusion

Chapter 4.  Initial Configuration of Asterisk

Section 4.1.  What Do I Really Need?

Section 4.2.  Working with Interface Configuration Files

Section 4.3.  FXO and FXS Channels

Section 4.4.  Configuring an FXO Channel

Section 4.5.  Configuring an FXS Channel

Section 4.6.  Configuring SIP

Section 4.7.  Configuring Inbound IAX Connections

Section 4.8.  Configuring Outbound IAX Connections

Section 4.9.  Debugging

Section 4.10.  Conclusion

Chapter 5.  Dialplan Basics

Section 5.1.  Dialplan Syntax

Section 5.2.  A Simple Dialplan

Section 5.3.  Adding Logic to the Dialplan

Section 5.4.  Conclusion

Chapter 6.  More Dialplan Concepts

Section 6.1.  Expressions and Variable Manipulation

Section 6.2.  Dialplan Functions

Section 6.3.  Conditional Branching

Section 6.4.  Voicemail

Section 6.5.  Macros

Section 6.6.  Using the Asterisk Database (AstDB)

Section 6.7.  Handy Asterisk Features

Section 6.8.  Conclusion

Chapter 7.  Understanding Telephony

Section 7.1.  Analog Telephony

Section 7.2.  Digital Telephony

Section 7.3.  The Digital Circuit-Switched Telephone Network

Section 7.4.  Packet-Switched Networks

Section 7.5.  Conclusion

Chapter 8.  Protocols for VoIP

Section 8.1.  The Need for VoIP Protocols

Section 8.2.  VoIP Protocols

Section 8.3.  Codecs

Section 8.4.  Quality of Service

Section 8.5.  Echo

Section 8.6.  Asterisk and VoIP

Section 8.7.  Conclusion

Chapter 9.  The Asterisk Gateway Interface (AGI)

Section 9.1.  Fundamentals of AGI Communication

Section 9.2.  Writing AGI Scripts in Perl

Section 9.3.  Creating AGI Scripts in PHP

Section 9.4.  Writing AGI Scripts in Python

Section 9.5.  Debugging in AGI

Section 9.6.  Conclusion

Chapter 10.  Asterisk for the Über-Geek

Section 10.1.  Festival

Section 10.2.  Call Detail Recording

Section 10.3.  Customizing System Prompts

Section 10.4.  Manager

Section 10.5.  Call Files

Section 10.6.  DUNDi

Section 10.7.  Conclusion

Chapter 11.  Asterisk: The Future of Telephony

Section 11.1.  The Problems with Traditional Telephony

Section 11.2.  Paradigm Shift

Section 11.3.  The Promise of Open Source Telephony

Section 11.4.  The Future of Asterisk

Appendix A.  VoIP Channels

Section A.1.  IAX

Section A.2.  SIP

Appendix B.  Application Reference

AbsoluteTimeout( )

AddQueueMember( )

ADSIProg( )

AgentCallbackLogin( )

AgentLogin( )

AgentMonitorOutgoing( )

AGI( )

AlarmReceiver( )

Answer( )

AppendCDRUserField( )

Authenticate( )

Background( )

BackgroundDetect( )

Busy( )

CallingPres( )

ChangeMonitor( )

ChanIsAvail( )

CheckGroup( )

Congestion( )

ControlPlayback( )

Curl( )

Cut( )

DateTime( )

DBdel( )

DBdeltree( )

DBget( )

DBput( )

DeadAGI( )

Dial( )

DigitTimeout( )

Directory( )

DISA( )

DumpChan( )

DUNDiLookup( )

EAGI( )

Echo( )

EndWhile( )

ENUMLookup( )

Eval( )

Exec( )

ExecIf( )

FastAGI( )

Festival( )

Flash( )

ForkCDR( )

GetCPEID( )

GetGroupCount( )

GetGroupMatchCount( )

Goto( )

GotoIf( )

GotoIfTime( )

Hangup( )

HasNewVoicemail( )

HasVoicemail( )

IAX2Provision( )

ImportVar( )

LookupBlacklist( )

LookupCIDName( )

Macro( )

MailboxExists( )

Math( )

MeetMe( )

MeetMeAdmin( )

MeetMeCount( )

Milliwatt( )

Monitor( )

MP3Player( )

MusicOnHold( )

NBScat( )

NoCDR( )

NoOp( )

Park( )

ParkAndAnnounce( )

ParkedCall( )

PauseQueueMember( )

Playback( )

Playtones( )

Prefix( )

PrivacyManager( )

Progress( )

Queue( )

Random( )

Read( )

RealTime

RealTimeUpdate( )

Record( )

RemoveQueueMember( )

ResetCDR( )

ResponseTimeout( )

RetryDial( )

Ringing( )

SayAlpha( )

SayDigits( )

SayNumber( )

SayPhonetic( )

SayUnixTime( )

SendDTMF( )

SendImage( )

SendText( )

SendURL( )

Set( )

SetAccount( )

SetAMAFlags( )

SetCallerID( )

SetCallerPres( )

SetCDRUserField( )

SetCIDName( )

SetCIDNum( )

SetGlobalVar( )

SetGroup( )

SetLanguage( )

SetMusicOnHold( )

SetRDNIS( )

SetVar( )

SIPAddHeader( )

SIPDtmfMode( )

SIPGetHeader( )

SoftHangup( )

StopMonitor( )

StopPlaytones( )

StripLSD( )

StripMSD( )

SubString( )

Suffix( )

System( )

Transfer( )

TrySystem( )

TXTCIDName( )

UnpauseQueueMember( )

UserEvent( )

Verbose( )

VMAuthenticate( )

VoiceMail( )

VoiceMailMain( )

Wait( )

WaitExten( )

WaitForRing( )

WaitForSilence( )

WaitMusicOnHold( )

While( )

Zapateller( )

ZapBarge( )

ZapRAS( )

ZapScan( )

Appendix C.  AGI Reference

ANSWER

CHANNEL STATUS

DATABASE DEL

DATABASE DELTREE

DATABASE GET

DATABASE PUT

EXEC

GET DATA

GET FULL VARIABLE

GET OPTION

GET VARIABLE

HANGUP

NOOP

RECEIVE CHAR

RECORD FILE

SAY ALPHA

SAY DATE

SAY DATETIME

SAY DIGITS

SAY NUMBER

SAY PHONETIC

SAY TIME

SEND IMAGE

SEND TEXT

SET AUTOHANGUP

SET CALLERID

SET CONTEXT

SET EXTENSION

SET MUSIC ON

SET PRIORITY

SET VARIABLE

STREAM FILE

TDD MODE

VERBOSE

WAIT FOR DIGIT

Appendix D.  Configuration Files

Section D.1.  modules.conf

Section D.2.  adsi.conf

Section D.3.  adtranvofr.conf

Section D.4.  agents.conf

Section D.5.  alarmreceiver.conf

Section D.6.  alsa.conf

Section D.7.  asterisk.conf

Section D.8.  cdr.conf

Section D.9.  cdr_manager.conf

Section D.10.  cdr_odbc.conf

Section D.11.  cdr_pgsql.conf

Section D.12.  cdr_tds.conf

Section D.13.  codecs.conf

Section D.14.  dnsmgr.conf

Section D.15.  dundi.conf

Section D.16.  enum.conf

Section D.17.  extconfig.conf

Section D.18.  extensions.conf

Section D.19.  features.conf

Section D.20.  festival.conf

Section D.21.  iax.conf

Section D.22.  iaxprov.conf

Section D.23.  indications.conf

Section D.24.  logger.conf

Section D.25.  manager.conf

Section D.26.  meetme.conf

Section D.27.  mgcp.conf

Section D.28.  modem.conf

Section D.29.  musiconhold.conf

Section D.30.  osp.conf

Section D.31.  oss.conf

Section D.32.  phone.conf

Section D.33.  privacy.conf

Section D.34.  queues.conf

Section D.35.  res_odbc.conf

Section D.36.  rpt.conf

Section D.37.  rtp.conf

Section D.38.  sip.conf

Section D.39.  sip_notify.conf

Section D.40.  skinny.conf

Section D.41.  voicemail.conf

Section D.42.  vpb.conf

Section D.43.  zapata.conf

Section D.44.  zaptel.conf

Appendix E.  Asterisk Command-Line Interface Reference

!

abort halt

Section E.1.  add

Section E.2.  agi

Section E.3.  database

Section E.4.  iax2

Section E.5.  indication

Section E.6.  logger

Section E.7.  meetme

Section E.8.  pri

Section E.9.  remove

Section E.10.  restart

Section E.11.  set

Section E.12.  show

Section E.13.  sip

Section E.14.  stop

Section E.15.  zap

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About the Authors

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Index

SYMBOL

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z