The OLSC interface is used by some software. I think HeLaserScan uses it, Spaghetti used to have a interface for it (they still might ... implemented as the FSX2 DAC interface...), and I think LSX also. Also it can be adapted to fairly easily with software to use the Mamba DLL interface. It was meant more as a common DLL library API for DACs to use to interface with software. The support for other laser show DACs is probably a bit out of date.
You may be better off implementing the Mamba DLL API and/or EasyLase DLL API (Dr. Lava's Sound Card DAC DLL API). The source code in the OLSC/OLSD pages has examples of both of these DLL API implementations I think.