The reason why our Spintrak webpage was not updated was because we discontinued the original unit some 8 months ago. So it was not available for purchase, out of stock in the store all of this time.
Our original Spintrak was designed before SMD reflective quadrature sensors were available, to enable the sensor to be made sufficiently small, and also much cheaper than before. This is why we discontinued it, because technology had advanced and we wished to take advantage of it. There was no reason to continue using a two-element transmissive sensor when one single SMD chip would work.
From the look of the TT2 I would think it uses a packaged sensor module from
www.usdigital.com. When this package became available it made absolute sense to use it in this application. But in fact we did find a manufacturer who was already making a complete compact encoder unit using an SMD reflective sensor chip. They are an "offshore" company (Not China) and our unit has their part number with a suffix for the type of connector we specified.
I do not consider adopting new technology "sleazy" just because another supplier is also using this technology. The KeyWiz uses the same chip as the I-PAC, no problem with that.
On the subject of USB 2.0 vs 1.1.
Using USB 1.1 gives a maximum data packet of 7 bits in each direction (8 bits total) ie 127 increments. The "poll rate" unless it is artificially increased is approx 7ms.
This means with 1200 pulses per revolution, that is 9.5 data packets per revolution which (in an ideal situation) would take 66.5 ms. This equates to a maximum speed of 15 revs per second. In testing we found it is easy to exceed this in gaming especially on "transients". Twisting the knob quickly easily exceeds 127 pulses.
USB 2.0 uses 15-bit data in each direction (in this case) and a faster poll rate and so there is no realistic restriction at all. The counter in the interface is 16 bits wide so can count any possible transient "twist".
As far as PS/2 goes, we dumped this altogether. Its quite difficult to calculate a maximum supported speed with PS/2 as there are so many factors, including the fact that the interface has to send each bit individually while trying to deal with the pulses from the encoder. The data rate will be limited to much lower than the theoretical maximum packet rate on the interface. For PS/2 its best to simply test performance. Adjusting mouse speed to lowest in Windows, and spinning at increasing rates. The speed limitation can be observed.
The 127-pulse transient limit also applies in PS/2.
Andy