Controller Type	Example pic	Products	Capability	(+) Pro	(-) Con
External or internal Sync Doubler	Neotek Model SS	professional products by Stereographics, Neotek, NuVision and others,  some pro-graphics boards & workstations	turns split screen into kind of page- flipping	stereo-orientation remains stable,   perfect compatibility to any graphics hardware, 100% VGA-chipset independent, NO driver software required, high refresh rates by default, easy setup, lots of prof. software, standard video codec (mpeg, avi,...) compatible	expensive (H3D is an exception),   lack of split screen consumer software (H3D might change that), always half resolution,   some lines are lost for the retrace gap,   pass-through-cable might deteriorate VGA-signal (*)
VGA-pass-through with general V-sync detection	i-Art	i-Art Virtual Eyes,  APEC-VR97,   Cyberstuff Cyber3DVisor(?),  Homebrew VGA-PT	syncs to all interlace and page-flipping screens	almost perfect hard- and software compatibility, easy setup, stereo reverse button, Windows support, little impact on CPU	stereo- orientation can flip very often in some cases, orientation has to be set manually each time, drivers required, pass-through-cable might deteriorate VGA-signal (*)
VGA-pass-through with general V-sync detection and line-blanker	VR-Joy	VR-Joy  CyberboyII (?) EyeFX	syncs to all interlace and page-flipping screens, creates artificial interlace on any graphics board	perfect hardware- and almost perfect software compatibility, easy setup, stereo reverse button, Windows support, little impact on CPU, no drivers required	stereo- orientation can flip very often in some cases, orientation has to be set manually each time, pass-through-cable might deteriorate VGA-signal (*)
VGA-pass-through with tweaked V-sync detection	VR-Surfer	VRex VRSurfer	syncs to all interlace signals, (page-flipping limited)	stereo-orientation remains stable,   auto-shut-off, high refresh rates easy to achieve, Windows support, reverse button, good software compatibility (next to VGA-pass-through), little impact on CPU, good results even on low-end monitors	VGA chipset dependend driver, no Rendition, 3DFX or other newer chipsets  supported, limited page-flipping support,  no line doubling, pass-through-cable might deteriorate VGA-signal (*)
VGA-pass-through with sync detection,  sync doubler and line blanker (synthetic interlace), controled by proprietary code pattern	H3D	H3D Eyewear	turns split screen into page-flipping, turns standard into "synthetic interlace", syncs to page-flipping	stereo-orientation remains stable, perfect compatibility to any graphics hardware, 100% VGA-chipset independent, NO driver software required, combines the advantages of sync doubler and  sync detection controllers (except for software compatibility), unique "synthetic interlace", easy setup when used with native software	no backward software compatibility whatsoever, no  support for non-H3D-certified software, requires H3D code pattern, no manual overrides, pass-through-box might deteriorate VGA-signal (*)
VGA-pass-through with White Line Code detection	SimulEyes	Stereographics-SimulEyes, miro-3D-fanatix	syncs to all interlace and page-flipping signals as long as White Line Code is present	stereo-orientation remains stable,   easy setup, no stereo reverse needed, Windows support, little impact on CPU	works with proprietary software only, WLC must stay on the screen all the time, pass-through-cable might deteriorate VGA-signal (*)
serial/parallel port		Nuvision-3D-SPEX, Woobo-Cyberboy, APEC-Virtual Visor, 3DTV-3D-Magic, Chinon-Cybershades,   homebrew-controller	syncs to page-flipping, requires  control software	stereo-orientation remains stable,      no pass-through cable in the way of the VGA-signal      [3D-SPEX supports Windows (not on Cyrix machines) and most DOS software, Cyberboy hasa stereo reverse button]	synchronization must be achieved by software, possible sync errors, impact on CPU, no interlace mode support, no Windows support (except limited support for 3D-SPEX & compatibles --WinSPEX !!!!), one serial or parallel port used (some products have a pass-through parallel solution)
3D-Max ISA card/on-board controller		Kasan-3D-Max, Kasan VGA cards with on-board controller,   (Russian Shield Stereo Set?)	syncs to Interlace, must be invoked by software	stereo-orientation remains stable,   high refresh rates easy to achieve, Windows support, good software compatibility (next to VGA-pass-through, even better in some rare cases), little impact on CPU, good results even on low-end monitors	VGA chipset dependend driver, no Matrox, Rendition, 3DFX or other new chipsets  supported, no page-flipping support (?), eats up an ISA slot, no line doubling, pass-through-cable might deteriorate VGA-signal (*)
(Canopus T3D) on-board controller		Canopus Total 3D	syncs to RAM-DAC (page-flipping)	stereo-orientation remains stable (?), no pass-through cable in the way of the VGA-signal	limited software compatibility (???), no interlace mode support, no Windows support (?)
(VESA) miniDIN-3 on-board connector (additional external controller circuitry required)		Glasses: StereoGraphics CrystalEyes, Z-Screen;  VGA-boards: Hercules Thriller, Hercules Stingray 128, Diamond Fire GL 1000 pro, dsystems GLadiator and more	syncs to RAM-DAC (page-flipping)	professional solution, standard of the future, stereo-orientation remains stable, no impact on CPU time, no pass-through cable in the way of the VGA-signal	not much consumer software support yet, no consumer glasses yet, doesn't drive glasses directly - additional controller circuitry required

The serial/parallel port controllers don't look that good here, but  Nuvision proved, by releasing WinSPEX and NuvFrag for 3D-SPEX , that a parallel (or serial) port device can achieve most of the things a VGA-pass-through controller can do, as long as the driver support is right. - It's all about software guys! Some companies don't look good when it comes to software support.
There's another advantage of ser/par controllers. The stereo-orientation is rock solid and you don't need to use a stereo reverse button all the time.
The upcoming SSDI universal driver will add windows support to all serial/parallel devices - hopefully.
There's no doubt however that VGA-pass-through controllers are easier to handle when it comes to driver tweaking.
 
 

To get a Shutterglasses system to work certain things have to be achieved. The number of steps depends on the controller used.

There are 3 steps - basically:

• Step 1: Get the VGA-card into 3D-mode (page-flipping or interlace)
• Step 2: Get the glasses working
• Step 3: Get a good synchronization between VGA-signal and glasses, in other words: play around with the timings

• Using a parallel/serial controller all 3 steps have to be achieved (sometimes tricky).
• Using a 3D-Max steps 1 and 2 have to be achieved only. (Sometimes I achieved only one of the two, which drove me crazy!!!)
• Using a VESA3 on-board connector proprietary software is required, but it'll work without any hassle.
• Using a White Line Code VGA-pass-through controller (what were they thinking?) only step 1 has to be achieved - in case the software supports WLC, if not you're marooned !
• Using a VGA-pass-through controller for interlace (VRSurfer) step 1 has to be achieved only, but if the screen shows a page-flipped image the glasses won't work in most cases.
• Using a plain VGA-pass-through controller step 1 has to be achieved only.
• Using a plain VGA-pass-through controller with line-blanker only a button has to be pushed. (Ahhhhh, what a relieeeeef.)