Asterisk 1.4 · The Professional's Guide by Duffett, David -- Read -- Imperial Library of Trantor

Index

Asterisk 1.4

Asterisk 1.4 Credits Foreword About the Authors About the Reviewers Preface

Reviewing the basics No compromise What this book covers Onwards Conventions Reader feedback Customer support

Downloading the example code for the book Errata Piracy Questions

1. The Dialplan

Dialplan location Extensions and contexts

Pattern matching Why use contexts? Call barring made simple Time and day call routing

Variables

Inheritance of channel variables through the dialplan

Using the AstDB

Dialplan features and additions

func_devstate

What can we use the DEVSTATE() function for?

Outgoing trunk selection Calling extensions Setting lights Boosting outgoing call capacity

Using multiple broadband lines

Configuration overview

Setting up the routing in Linux Configuring Asterisk Explanation of the macro Downsides

System() application

Summary

2. Network Considerations when Implementing Asterisk

Centralized and distributed installations

Centralized installations Distributed solutions Latency and jitter Jitterbuffer Echo

Do your homework

SLAs are for everyone Achieving the goal Backups To share or not to share Ensuring quality When things go wrong

Red Amber Green

Increasing resilience

Summary

3. Call Routing with Asterisk

Routing methods Where to start Internal calls Local calls National calls International calls Alternative options

ENUM DUNDi

Types of routing Routing techniques Summary

4. Call Centers—Queues and Recording

Asterisk queues

Queue gotchas

A practical queue Using queues to cascade calls

Call recording—the issues

Show-stoppers

VoIP recording approaches Impact of VoIP on recording systems

Hardware convergence

Distributed call centers

Home working

VoIP recording challenges

Routing Bandwidth Encryption Solutions

Asterisk call center solutions

How VICIDIAL works

Handling inbound calls Installation Timing sources Scalability

Summary

5. Asterisk and Speech Technology

Why speech-enable? Types of speech technologies

Automatic Speech Recognition (ASR)

Isolated Word Recognition Connected Word Recognition Natural Language Recognition

Text-to-Speech (TTS) Speaker Verification and Identification (SVI)

MRCP

Implementation considerations

ASR and Asterisk

Installing LumenVox speech recognition with Asterisk Checking that things are working

SpeechCreate() SpeechLoadGrammar (yesno,/etc/lumenvox/Lang/BuiltinGrammars/ABNFBoolean.gram) SpeechActivateGrammar(yesno) SpeechBackground(beep) Verbose(1,Result was ${SPEECH_TEXT(0)}) Verbose(1,Confidence was ${SPEECH_SCORE(0)}) SpeechStart() SpeechDeactivateGrammar(label) SpeechUnloadGrammar(label) SpeechDestroy() ${SPEECH(results)}

Grammar files Implementation advice for ASR

TTS with Asterisk

Implementation advice for TTS

Summary

6. Call Accounting and Billing

Call Data Records (CDRs)

CDR frontends

Call accounting Providing termination billing

Every little helps Selecting a billing platform Introducing A2Billing

Reasons to consider A2Billing A2Billing requirements Monitoring usage Coding for A2Billing

Billing gotcha! High call volumes