High performance VoIP SDK for .Net developers

VoIP SIP SDK

"Who Else Wants to Create VoIP Applications efficiently?"

Ozeki VoIP SIP SDK will save you a lot of time. It will make you much more efficient when you build voice and video applications. You can concentrate on your project, the true functionality you want to achieve. This excellent toolbox gives you all the tools you need to create telecommunication solutions efficiently. Try it now ...

Softphone   Webphone   Callcenter, CRM, IVR
An excellent tool to build your own softphone or SIP client application

Build your own softphone
SIP voice calls
SIP video calls
SIP DTMF signaling
Conferencing
  Enables you to add a video phone to your website using Adobe Flash or MS Silverlight

Silverlight to SIP calls
Adobe Flash to SIP calls
Browser to browser calls
Webbrowser to VoIP calls
Javascript call management
  Can be used to add functionality to your call center, IVR or CRM

Build your own IVR
Voice recognition IVR system Voice Activation Detection Auto and predictive dialer
Call recording


Ozeki VoIP SIP SDK Product information (full datasheet)
Category Software Development Kit
Main task Makes it possible to build IP based telephone solutions, such as softphones, webphones, and VoIP client software based on the SIP protocol. Works with VoIP PBX systems and Internet based VoIP service providers.
Performance With our platform you can build telephone solutions that can serve several thousand simultaneous voice/video calls.
Connectivity It connects to a VoIP PBX or to a VoIP service provider over the Internet. Supports firewall passthrough (STUN).

VoIP applications included in Ozeki SIP SDK package with full source:

Ozeki has released the source code for many popular VoIP applications requested by customers. You are free to use these applications and the code that comes with them:

Voice softphone solutions

  1. A customizable C# softphone example
    An excellent C# software phone for SIP voice calls with Windows Presentation Foundation graphical user interface.
  2. Windows Form Softphone example
    A great C# softphone solution for SIP voice calls using Windows Forms technology for the user interface.
  3. A customizable VB.Net softphone example
    A nice voice softphone example program written in Visual Basic.NET. A great opportunity to get the knowledge about how to use a C# SDK from VB.NET.
  4. A simple softphone application for the basic voice call purposes
    A C# softphone application that covers all the basic voice call functions with a detailed step by step guide for better understanding.
  5. A Visual C++.Net softphone example program
    A great softphone example that demonstrates how you can use the C# SDK in a Visual C++.NET environment.
  6. A softphone for forwarding calls
    A C# softphone example that introduces the call forward and call transfer functions.
  7. A softphone for call holding function
    A professional C# softphone extended with call holding function.
  8. An auto answering softphone example
    A C# softphone solution with auto answer function. This can be a great base for an answering machine or an IVR or Call center server.
  9. SIP/SDP message manipulator softphone
    An advanced softphone solution that demonstrates the possibilities of Ozeki VoIP SIP SDK support for SDP and SIP message manipulation.
  10. Windows Forms Softphone with Do Not Disturb functionality
    A simple C# softphone application extended with Do Not Disturb functionality.
  11. Windows Forms softphone with .mp3 and .wav playing support
    A C# softphone solution that shows the possibility of playing an .mp3 or .wav audio file into a SIP voice call.
  12. A softphone for multiple phone lines
    An advanced C# softphone application that is able to handle two phone lines.
  13. A softphone example for call recording
    An advanced C# softphone example program that records all the phone calls that is made by it. The recorded audio file stores both the incoming and outgoing voices.
  14. A softphone with blind transfer function
    A great softphone application that demonstrates how you can use the blind transfer function of the Ozeki VoIP SIP SDK.
  15. A softphone for multiple phone calls
    An advanced softphone solution handling multiple phone calls at the same time.
  16. A conference call example
    An advanced C# application for demonstrating how you can implement a client mixed conference call with Ozeki VoIP SIP SDK.

Video softphone solutions

  1. A C# video softphone
    An excellent C# video phone application that demonstrates the video telephoning features that can be implemented using Ozeki VoIP SIP SDK.
  2. Videophone example with codec and resolution modification support
    A video softphone example program that demonstrates how you can change the video device, video resolution and transmission codec in a softphone application.

Webphone solutions

  1. Silverlight Video Chat Example
    A website embedded video chat program using Microsoft Silverlight technology for the client-side solution.
  2. Mediagateway Easy Connection Example
    A great example for Silverlight embedded softphone building with Ozeki VoIP SIP SDK.
  3. Mediagateway SIP Example
    An example program that demonstrates how you can build a Silverlight SIP application.
  4. Flash SIP Example
    A professional SIP example for introducing the possibilities of Flash.
  5. Mediagateway SDK Flash Chat Example
    A video chat example using Flash technology for the client side solution.
  6. Silverlight SIP softphone
    A great Silverlight website embedded softphone example program with detailed code introduction.
  7. Web to web voice calls using Silverlight
    Silverlight webphone example program for web to web voice communication.
  8. Web to web video calls using Silverlight
    A professional Silverlight website embedded video telephone program.
  9. How to add a Silverlight webphone to a web page
    An advanced application that demonstrates how you can integrate your Silverlight webphone into a web page with Javascript technology.
  10. Flash SIP softphone
    A fully featured softphone application that can be embedded into a website with Flash client interface.
  11. Web to web voice calls using Flash
    A Flash voice webphone application for web to web communication.
  12. Web to web video calls using Flash
    An advanced video telephone application using Flash technology for web to web video communication.
  13. How to add a Flash webphone to a web page
    A Flash softphone example program that introduces the usage of Javascript in embedding a webphone into a website.
  14. A Flash web conference example
    An advanced solution for webinar or web conferencing purposes implemented in Adobe Flash.

IVR solutions

  1. DTMF IVR example
    A professional IVR solution that operates with DTMF signals.
  2. Voice recognition IVR example
    A great example that demonstrates how you can build an IVR system that uses voice recognition for navigation.
  3. WinForms DTMF IVR
    An advanced IVR solution with DTMF IVR tree navigation.
  4. XML-based IVR solution with DTMF navigation
    An auto answering C# IVR system that builds up the IVR tree from an XML file, uses Text to Speech conversion for reading up the IVR messages and handles the tree navigation with the received DTMF signals.
  5. IVR solution with Speech to Text recognition navigation
    An auto answering C# IVR system that uses an .xml file for building up the IVR tree
  6. VB .NET DTMF IVR
    An auto answering DTMF navigated IVR system written in Visual Basic .NET.

PBX solutions

  1. Your first Ozeki C# PBX
    The easiest way to implement a professional PBX system with full functionality using Ozeki VoIP SDK.
  2. PBX authentication
    Implementing SIP authentication in an Ozeki VoIP PBX solution.
  3. PBX dial plan implementation
    Extending an Ozeki VoIP PBX system with customized dial plans.
  4. PBX voice mail extension
    Implementing voice mail virtual extension for an Ozeki VoIP PBX solution.
  5. PBX webphone extension
    Connecting a webphone solution to an Ozeki VoIP PBX.
  6. PBX IVR extension
    Extending an Ozeki VoIP PBX with a virtual extension for IVR functionalities.
  7. PBX call manager
    The easiest way to implement a call manager for an Ozeki VoIP PBX.
  8. Advanced PBX call manager
    A professional call manager implementation for an Ozeki VoIP PBX.

Call Center solutions

  1. Voice Activation Detection Example Program
    A great example program that demonstrates the usage of the Voice Activation Detection technology provided by Ozeki VoIP SIP SDK.
  2. Predictive Dialer Example Program
    A predictive dialer program that show how you can use Ozeki VoIP SIP SDK for specifying if a person or an answering machine answered the call.

Mobile platform solutions

  1. Mobile to web voice calls on Android platform
    The easiest way to connect an Android mobile device to a VoIP communication network with Ozeki VoIP SDK.
  2. Mobile to web video calls on Android platform
    A professional video phoning solution for Android mobile devices.
  3. Mobile to SIP calls on Android platform
    Android platform application for SIP voice communication.
  4. Mobile to web voice calls on Apple platform
    Integrating Apple devices into a VoIP communication system with voice calling possibilities.
  5. Mobile to web video calls on Apple platform
    Advanced video calling solution for Apple devices using Ozeki VoIP SDK.
  6. Mobile to SIP calls on Apple platform
    Ozeki VoIP application for SIP calls on Apple mobile devices.
  7. Mobile to web voice calls on Windows Phone 7 platform
    A revolutionary VoIP solution for Windows Phone 7 platform only with Ozeki VoIP SDK.
  8. Mobile to web video calls on Windows Phone 7 platform
    The very first possibility for video calling on Windows Phone 7 devices.
  9. Mobile to SIP calls on Windows Phone 7 platform
    A unique Ozeki VoIP communication program for SIP voice calls.

Ozeki VoIP Training example programs

  1. Ozeki VoIP Training Softphone Example Program
    A detailed guide for building a C# softphone application with Ozeki VoIP SIP SDK.
  2. Ozeki VoIP Training Answering Machine Example Program
    A developer's guide for creating an answering machine application with Ozeki VoIP SIP SDK.

Further example programs

  1. C# Autodialer example
    A great example for an autodialer system that can be built with Ozeki VoIP SIP SDK.
  2. C# speech to text example
    An excellent example program for demonstrating how you can use the speech to text conversion with Ozeki VoIP SIP SDK.
  3. Voice conference room example
    An example application that shows the possibility of voice conferencing provided by Ozeki VoIP SIP SDK.
  4. Command line caller example
    An example program that introduces the command line caller technology provided by Ozeki VoIP SIP SDK.
  5. SIP SMS example
    An advanced example program that shows the SIP SMS sending solution that can be created by using Ozeki VoIP SIP SDK.
  6. Callback form example
    A great example for creating a callback form with Ozeki VoIP SIP SDK.
  7. ASP VoIP example
    A great example program that demonstrates how you can use ASP programming language for building a VoIP solution with Ozeki VoIP SIP SDK.
  8. Voice recognition with Speech to Text conversion
    A C# example program that introduces the possibility of voice recognition with Ozeki VoIP SIP SDK.
  9. Example program for audio conversions
    A C# example program that contains all the possible audio conversions in all variations that can be made by using Ozeki VoIP SIP SDK.

For more information please contact us at info@voip-sip-sdk.com!

Use Ozeki VOIP SIP SDK in your .Net project and make VoIP calls immediately!

Download (.zip)  
The complete manual
Data Sheet (.pdf)
Screenshots
Code sample
Demo Softphone program


Facts about Ozeki VOIP SIP SDK:

1. It is a true .NET solution
All functionality of the SIP protocol is implemented in C#.NET using managed code. This is a huge advantage. Learn more...

2. Outstanding compatibility
Ozeki VoIP SDK is compatible with the following PBX systems. Check out how to configure the SDK to connect to them!
Cisco Unified CM configuration
Cisco Call Manager Express configuration
Asterisk configuration
3CX configuration
AsteriskNow configuration
Kamailio configuration
FreeSwitch configuration
OpenSIPS configuration
SipX ECS configuration
Trixbox configuration
OpenSER configuration
PBXnSIP configuration
PBXpress configuration
Elastix configuration
FreePBX configuration
SwyxWare configuration
Aastra MX-One configuration

3. Supports on-line VoIP services
Ozeki VoIP SDK is fully standard complient. It works with almost all VoIP service providers. We recommend you to use the following services:

Skype Connect configuration
Axvoice configuration
Gafachi configuration
Callcentric configuration
SureVoIP configuration
VoIPtalk configuration

4. Outstanding support
You can expect fast reaction times and excellent service from our software developers, who are constantly improving this SDK.

5. Extended codec support
Ozeki VoIP SIP SDK has been developed to ensure excellent sound quality. For this purpose various codecs are supported effectively:

G711 Alaw
G711 Ulaw
G722
G729
iLBC
Speex
GSM

6. Customizable features and GUI
You can easily customize the features and GUI of your softphone when you use Ozeki VoIP SIP SDK. For some softphone GUI design ideas please check: Softphone GUI page!

7. It is based on IETF standards
The Ozeki VoIP SDK is implements the following standards to meet the requirements of commercial VoIP providers and PBX systems:

RFC 2833:RTP Payload for DTMF Digits, Telephony Tones and Telephony Signals
RFC 3261:Session Initiation Protocol
RFC 3263:SIP: Locating SIP Servers
RFC 3264:An Offer/Answer Model with the (SDP)
RFC 3265:SIP Event Notification
RFC 3420:Internet Media Type message/sipfrag
RFC 3428:SIP Instant Messaging
RFC 3489:STUN - Simple Traversal of UDP Through NATs
RFC 3515:SIP Refer Method
RFC 3550:Real-time Transport Protocol
RFC 3551:RTP Audio/Video Conference
RFC 3587:IPv6 Global Unicast
RFC 3666:SIP, PSTN, Call Flows
RFC 3725:Best Practices for Call Control
RFC 3842:Message Waiting Indication
RFC 3856:Presence Events in SIP
RFC 3891:The SIP Replaces Header
RFC 3892:SIP Referred-By Mechanism
RFC 3920:Extensible Messaging and Presence Protocol (XMPP): Core
RFC 4566:Session Description Protocol
RFC 5411:A Hitchhiker's Guide to the SIP

Read more about how various standards are used in VoIP in the Ozeki SIP Standard Overview page!