To access RS485 driver from Windows NT is actually easier than Windows 95. Install the RS485NT.SYS driver and open a channel to the driver using the CreateFile() function. Then, read and write information using ReadFile() and WriteFile() functions. Baud rate and the like are configured using registry entries. The device driver handles all of the RS-485 multi-drop RTS drive enable issues for Models: 485-25A and 485-25I.