LabView can be used to interface to the U4x1 devices. LabView uses the USBm.dll DLL.
There are updated documents on the LabView (National Instruments) website that describe how a DLL is interfaced to LabView. Look for a document titled: “Using External Code in LabVIEW”.
A very special thanks to Amadeo Vergés for creating this USBmicro LabVIEW Driver (see downloads).