In the last couple of days a colleague and I have been playing with the new SimplePhone SDK sample, that will be downloadable from the DRC in the next few days. This couples a VB.NET soft-phone application with an Audio Provider DLL (written in C) that handles the streaming between the soundcard and the SIP/VoIP stack in your PC.

There are three goals for this new sample:

1. To demonstrate how in VB.NET you can easily make your own SoftPhone code
2. To show how the Audio Provider part of the SDK is used
3. To show that apps in C and apps in VB.NET can co-operate to get the job done with our SDK. VB is great at prototyping, and all the GUI stuff, where C is really great at handling the streaming audio, and hiding the real-time tasks away from the main application.

With the SimplePhone app and Diva Server SoftIP 2.0 loaded up on our laptops, we were able to register with accounts on the SIP Express Router (SER) site run by Iptel/Fraunhofer Fokus, and make SIP voice calls back and forth between us. SER is one of the longest established SIP Servers and SIP protocol stack, and there are are plenty of great telephony features there to play with.

Don't forget that you can still claim your free 30 day evaluation version of SoftIP, and have a go at this yourself.