HID (Human Interface Device ) is a cross platform USB input device driver developed by Microsoft.  The HID interface provides flexible data reporting for game simulation input devices.   HID allows the input device to define itself to Windows 98/2000 by way of a report descriptor , describing buttons, axes, sliders, throttle etc….   This allows an developer to adapt input devices with ease to a unified cross platform device driver.   For more info-- http://www.microsoft.com/hwdev/