Asterisk 1.4 : The Professional’s Guide电子书

Asterisk 1.4

Table of Contents

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

Other high-call-volume solutions

SER/OpenSER

FreeSWITCH

Summary

7. Resilience and Stability

Increasing availability

Stability

Network

Cables

Switches and routers

Endpoints

Telephony switches and gateways

Server

Environment

Dealing with failure

Network resilience

Server

High availability

Ultra Monkey

Telephony switches/gateways

Redfone foneBRIDGE2

Junghanns ISDNguard

Endpoints

Round robin DNS

Say hello to Rsync

Limiting the number of calls per server

Summary

8. Localization and Practical Security

Tones

Time and date and localization

Changing the language of system prompts

Local telephony interfaces

Analog

Digital

Localizing caller ID signaling on Digium analog interfaces

Checklist

Practical security

Out of hours

Summary

9. Interfacing with Traditional Analog and Digital Telephony

Analog

Digital

ISDN BRI (Basic Rate Interface)

ISDN PRI (Primary Rate Interface)

Choices, choices

Using external adaptors

Using cards

Installing a Digium card

Card installation—physical

Installing the DAHDI software

Configuring the DAHDI files to enable the card

What about the other cards?

framing

coding

Troubleshooting with Digium cards

Summary

10. Integrating Asterisk with Wireless Technologies

Why integrate Asterisk with wireless technologies?

Wireless technology overview

Wi-Fi (only) phones

SIP desk phones with a wireless link

Dual-mode (GSM and SIP) phones and PDA/smart phones

SIP/DECT phones

Connecting Asterisk to mobile networks

Why connect to mobile networks?

The GSM gateway (box)

The GSM card

Configuring wireless devices

Configuring Asterisk to work with wireless technologies

Deployment choices

Neat money saving tricks

Calling a mobile phone

Avoiding those nasty roaming charges that arise from receiving calls

Summary

11. Graphical User Interfaces

Reasons for going GUI

Good to GUI

Ease of administration

Access to enhanced features

Easier upgrade process

Standardized code

GUI, phooey!

Performance

Stability

Restricted functions

FreePBX

How it works

Installation

Configuration

Extensions

Inbound routes

Outbound routes

Trunks

Other records

Summary

A. Selling Your Solution

In the beginning ...

Drivers for changing phone systems

A word on cost

Generating interest

Alliances

Advertising

Search engines

Become an expert

Relationship marketing

Email as a marketing tool

Tracking prospects

Converting the prospect into a sale

Determining your customer's hardware requirements

Choosing the right phones

Tales of woe

Aastra

Linksys

Siemens Gigaset IP DECT phones

Snom M3

Remote support

Make it secure

Do's and don'ts

The do's

First impressions

Get brochures printed

Take notes

Send the quote in a timely manner

Follow up the quote

Target the decision makers, but don't ignore IT

The don'ts

You don't need a fancy office

Don't cut corners on the solution

Don't under price

Don't have a huge margin on handsets

Don't supply a PC as the phone server

Summary

B. Sample Email Content

What is VoIP?

Why should I consider VoIP?

Cost savings

Call costs

Line rental costs

Wiring costs

Reduced infrastructure costs

Centralized management

System integration

Unified messaging

Reliability

Closed and open systems

Superior sound

Fallback solutions

Broadcasting calls

A number for life

Number porting

Local numbers

About XYZ

Our philosophy

Our passion

C. Sample Appointment Sheet

Index