A golf simulator is a piece of hardware combined with software that allows you to simulate the game of golf.
A more detailed description: A technologically advanced machine that can sense, record, and analyze your swing and show you results like club speed, clubface angle and impact, club path, ball path, ball speed, horizontal and vertical launch angle, spin, and so on with simulator mats, sonic sound system, optical sensor system, radar, ball tracking system, and cameras.
Every simulator captures and senses these data points a little differently so it is important to get to know how your simulator works best with lighting, positioning, and so on.
There are a variety of manufacturers of golf simulator hardware. Several of those manufactures utilize E6 Connect software as the driving engine.