This Velleman USB Experiment Interface Board Kit has 5 digital input channels and 8 digital output channels. In addition, there are two analogue inputs and two analogue outputs with 8 bit resolution. With the K8055N interface board kit the number of inputs 7 outputs can be further expanded by connecting more (up to a maximum of four) cards to the PC's USB connectors. All communication routines are contained in a Dynamic Link Library (DLL). You may write custom Windows (XP, Vista, Windows7) applications in Delphi, Visual Basic, C++ Builder or any other 32-bit Windows application development tool that supports calls to a DLL. Source code examples for Visual Basic, Visual C++, Visual C#, Excel, Delphi and Borland C++ builder are available.