TrackIR was first created as an assistive head tracker for hands-free mouse emulation, priced at $99 in 2001, the NaturalPoint (then Eye Control) President was reported in the Corvallis Gazette Times saying:
"Eye Control's current goal is to bring eye, head and hand tracking to a mass market ... the technical trickle down ultimately could yield a $25 device for people with disabilities."
Instead of reducing the price for people with disabilities, mouse emulation was moved to a new camera brand called SmartNav and the price quadrupled, bringing it closer to that of competing assistive systems which have poor economies of scale. TrackIR retained mouse emulation in games with a separate executable called TIRMouse designed not to work in Windows properly. NaturalPoint have the benefit of the now gaming focused TrackIR, with a wider market and greater cost effectiveness, but have been unprepared to share this benefit with people who have assistive needs.

When running SmartNav software with a TrackIR camera, it reports;
"A TrackIR device was detected. This software only works with SmartNav devices."
But immediately after this message, mouse emulation can be seen to work very briefly, hinting that the two cameras are interchangeable and fundamentally the same. This can be confirmed with SmartNavFixer which shows it is an artificial limitation to justify the more expensive SmartNav brand.

SmartNav cameras are divided into two different models, AT and EG, but differ only in the way SmartNav software treats them. The more expensive AT model is targeted at hands-free use, working with click helper software called Dwell Clicker which comes bundled with SmartNav software. Oddly, Dwell Clicker functions perfectly on its own and with other software including FreeTrack, but SmartNav software actively prevents it from running with non-AT models by searching for it and immediately shutting it down with the message;
"The Dwell Clicker is not supported with this version of the hardware."
NaturalPoint have deliberately crippled their software in unusual ways and blamed it on hardware so they can justify charging a premium for very basic mouse emulation functionality and even more for click functionality, arbitrarily discriminating against people who need assistive technology to use a computer.

SmartNav software 3.20.x.x camera discrimination can be removed by extracting and executing SmartNavFixer.exe in the SmartNav folder. The fixer is only intended to demonstrate the artificial limitation, if you don't agree with NaturalPoint's terms you should not use their software and consider alternatives.

Download SmartNavFixer v1.0.0.7