Ozeki VoIP SIP SDK ensures professional technology for developing softphones
efficiently. You will find detailed documents on softphone
development basics and on advanced
softphone development. In order to make your work more successful, Ozeki
SIP SDK also offers outstanding softphone example programs. Furthermore, you
can also check the source codes of these programs and you can use these
codes in your project, as a starting point.
C# WPF softphone An excellent C# software phone for SIP voice calls with Windows Presentation Foundation graphical user interface.
Windows Forms Softphone VB.NET 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.