This .DLL is used by WinGPIB, see WinGPIBproj.
NOTE: Installation .MSI for WinGPIB is located in one of the other Repositories, here: \WinGPIBadditionalinfo\WinGPIB-AnyCPU_All-SetupFiles
Here is a list of the current interface that are confirmed WinGPIB compatible:
GPIBDevice_NINET - NI boards
GPIBDevice_ADLink - ADLink boards
GPIBDevice_gpib488 - Keithley, MCC and older NI boards
VisaDevice - Generic interface (GPIB,USB etc.) via Visa
COM Port - Generic serial ports
Prologix - Prologix USB and Ethernet
NI-GPIB-232CT-A - Serial
Kofen's PoE Ethernet - Prologix compatible
XYPHRO UsbGpib - Visa
Here is a link to Pawel's original IODevices.dll code that I had used as a basis for my mods: