Motivation behind VoIP
Single-site VoIP systems (VoIP LAN)
Multi site VoIP systems (VoIP WAN)
VoIP � PSTN connections
VoIP in mobile networks (IMS, VoIP, Skype)
VoIP on the Internet
Peer to peer VoIP client connections

Telephone system
PBX
VoIP telephone SET
VoIP telephone adapters
Softphone
SIP Account
SIP phone line
SIP phone call
ATA (FXS, FXO)
Call Center Server
Call Center Client
IVR
Webphone (client and gateway, Flash and Silverlight)

SIP
RFC document list
UDP
SDP
RTP
RTCP
H323

Codecs

G711 Alaw
G711 Ulaw
G722
G729
iLBC
Speex
GSM

III. The Ozeki VoIP SIP SDK

Installation

Download information
Package contents
System requirements
Installation steps
Opening and compiling your first project
Product activation
Product activation in the development server
Automatic license configuration

Tools provided by the SDK

Introduction to the technology
The Ozeki VoIP component model
SIP protocol implementation
RTP implementation
RTCP implementation
Audio device support (mic, speaker)
Audio encoding / decoding (audio codecs)
Voice quality tools (AEC, AVG, NR, Jitter buffer)
Video device support (camera and playback)
Video encoding / decoding (video codecs)
Implemented network protocols: UDP, TCP
Firewall passthrough (STUN, TURN)
Implemented file formats (mp3, wav, avi)

VoIP products you can build

Softphone
VoIP client applications: Dialers
Call assistant
Call center clients
Call center servers
PBX systems
IVR systems
Webphone solutions
Conferencing systems
Voice recording systems
VoIP tunneling systems
Security monitoring systems
Mobile communication systems

Capacity and performance

Multiple lines
Multiple calls
Performance (video encoding/decoding)

Developers Guide

Softphone Development

How to build a softphone (introduction)
How to build a softphone using Ozeki VoIP SIP SDK
Softphone example programs

C# WPF softphone
Windows Forms Softphone VB.NET
Windows Forms softphone sample
Visual C++ softphone

Softphone Development Basics

How to register to a SIP PBX
How to make a voice call (and play a wav)
How to use audio devices (microphone, speakers)
How to play voice from the microphone into a SIP voice call
How to play an mp3 file into a voice call
How to play voice using text to speech synthesis in a voice call
How to play incoming voice on the speaker
How to recognize incoming voice using speech to text conversion
How to accept an incoming call (and record a wav)
How to reject an incoming call
How to forward an incoming call
How to transfer an incoming call using blind transfer
How to transfer an incoming call using attended call transfer
How to hold a call
How to use DTMF and signaling (sending/receiving DTMF)
Working with SDP in VoIP SIP calls
Working with RTP in VoIP SIP calls
How to implement Auto Answer (AA)
How to implement Do Not Disturb (DND) functionality
How to make a video call (and play an avi)
How to use video devices (camera, video playback)
Addressing video quality (resolutions, codecs)

Advanced Softphone Development

How to manage multiple phone calls at the same time
How to manage multiple phone lines at the same time
How to make a client mixed conference call
How to record a voice call (mixing and recording incoming and outgoing audio)
How to capture/cancel or modify incoming SIP messages
How to inject SIP messages into a communication
How to capture/cancel or modify outgoing SIP messages
How to send out of dialog SIP messages
How to implement Message Waiting Indication (MWI)

Addressing sound quality in VoIP calls

The differences between 8 bit audio codecs and 16 bit high definition audio codecs
How to use the jitter buffer and how to handle latency
How to implement Acoustic Echo Cancellation (AEC)
How to implement Noise Reduction (NR)
How to use Automatic Voice Gain

Softphone customization

Custom WPF GUI and brandname
Custom winforms GUI and brandname

How to make a call directly between two SIP clients (peer to peer calls without a PBX)
How to make calls through firewalls (NAT traversal)
How to tunnel calls through VoIP blocked environments
How to encrypt calls with RTP encryption (SRTP, TLS)
How to encrypt calls with SIP encryption
SIP Instant Messaging and presence

How to send a SIP Instant Message
How to receive a SIP Instant Message
How to handle presence information in SIP Instant Messaging

Webphone Development

Introduction to Webphone technology (Flash vs. Silverlight vs. ActiveX, Client server model, HTTP tunneling)
Webphone example programs

Silverlight Video Chat Example
SLMediaGatewayEasyConnection Example
MediaGateway SIP Example
Flash SIP Client Example
MediaGateway SDK Flash chat example

Silverlight solutions

How to add a webphone to a webpage (silverlight camera and mic access)
Web to phone calls using Silverlight to SIP technology
Web to web voice calls using Silverlight webphone
Web to web video calls using Silverlight webphone
Add new functionality to a Silverlight webphone on the client side
Silverlight webphone javascript integration
Building a webinar/web conferencing system using Silverlight webphone technology
Facebook to SIP calls using Silverlight webphone
Facebook to Facebook calls using Silverlight webphone

Flash solutions

How to add a webphone to a webpage (Flash camera and microphone access)
Introduction to Flash webphone technology
Web to phone calls using Flash to SIP technology
Web to web voice calls using the Flash webphone
Web to web video calls using the Flash webphone
How to add functionality to a Flash webphone on the client side
Flash webphone javascript integration
Building a webinar/web conferencing system using Flash webphone technology
Facebook to SIP calls using Flash webphone
Facebook to Facebook calls using Flash webphone

Voice recording

Recording / playing back media in a softphone
Media stream to file and file to media stream conversion with different file formats and format conversions (using wav, mp3, avi, mpg, raw audio, video)

IVR development

IVR example programs

C# DTMF IVR
C# Voice recognition IVR WinForms DTMF IVR

How to build a multichannel IVR server (accepting calls and playing back wav audio)
Navigation in the IVR tree using DTMF commands
Navigation in the IVR tree using Voice recognition
Automated information query solutions (IVR database integration)
IVR to live operator transfer and take back (IVR human cooperation)

PBX development

How to build a simple PBX / registering extensions and setting up calls
How to connect your PBX to the outside world: SIP trunk management
Default VoIP PBX functionality
VoIP PBX authentication settings
VoIP PBX Dial plans
VoIP PBX virtual extensions
VoIP PBX Voice Mail
VoIP PBX Call Manager
Advanced VoIP Call Manager
VoIP PBX Call Assistant
VoIP PBX MediaGateway connection
How to connect two PBX systems to work as one

Call center development

How to build a simple call center server
Automatic Call Distribution

Introduction to Automatic call distribution / call routing
Building a simple call distribution system for inbound calls
SBR: Building a simple skill based routing engine (language, technical, etc)
How to create and manage call queues
Implementing callback requests in call queues
Using SIP presence and availability in call routing

Manager

How to listen in and take over calls
Monitoring call center activity in real time

Operator

Controlling a physical telephone from the PC (instruct to make/transfer a call)
Detect incoming phone call and display information based on caller id
Automated database information retrieval on phone ring / phone dial
Caller identification of outgoing calls based on Dialed number
Caller authorization using DTMF pin codes
Call information logging into a database

Automation

Building an auto dialer system using DTMF response to transfer to agent
Voice Activation Detection
Building a predictive dialer system (detect fax, busy signal, human voice)

Building a multi-site call center
The best way to connect remote call center agents to a call center over the Internet
Connecting remote agents to the call center (VoIP SDK secure tunneling solution)
Reaching clients on Facebook using Webphone technology

VoIP CRM integration

Adding VoIP support to a web based CRM using webphones
Adding VoIP support to a web based CRM using SIP based desktop phones
Recording calls and call details on a customer datasheet for both incoming outgoing calls
Bringing up a customer datasheet automatically on incoming calls

Mobile phones and platforms

How to connect mobile devices to a VoIP network
How to build an Android VoIP client
How to build an iPhone / iPad VoIP client

SIP, VoIP billing, cost management

Billing by minutes or seconds
Billing by call setup
Prepaid billing systems in VoIP networks
Postpaid billing systems in VoIP networks
Automated credit card payment systems (PayPal, ShareIt, Charging, Subscription, Chargeback)

Further VoIP SIP SDK Examples

C# Autodialer example
C# speech to text example
C# voice conference room
C# command line caller
SIP SMS Example
C# Callback Form
ASP VoIP Example

Appendix

Glossary (Terms and Definitions)

Detailed Feature list

Reference book

VoIP PBX compatibility

Cisco Unified CM
Asterisk
3CX
AsteriskNow
Kamaillo
FreeSwitch
OpenSIPS
SipX ECS
Trixbox
OpenSer
PBXnSIP
PBXpress
Elastic
FreePBX
SwyxWare

VoIP Service Provider compatibility

Skype Connect
Gafachi
CallCentric
SureVoIP
VoIPTalk

VoIP service providers by country

Troubleshooting

Wireshark Log

FAQ
SDK Exception Codes

Table of Contents

I. Introduction

II. VoIP technology

III. The Ozeki VoIP SIP SDK

Developers Guide

Appendix