So what happens is, A and B have pullups on them and will generate a square wave on the brush when rotated as the brush hits the ground trace on the wheel. Then about a third of the way out a brush (the A signal), then two thirds of the way out another brush (the B signal) that picks up the trace after the dogleg. One toward the center that contacts the ring.

Then, in the sensor there are three brushes. On that disk are traces that look like spokes emanating from a solid ring near the axle, but about halfway out, they dogleg a bit, and then continue out to the edge. I have one in a box somewhere, Envision an axle with a disk on the end, kind of like a dremel cutoff bit. If you have one of those machines from that era that came with proprietary interfaces, maybe you can make use of. The supply of still-reliable RS232 mice must therefore be dwindling, and if you have a Windows 3.1 PC to keep alive then we can see the ability to use a more modern pointing device has a lot going for it. In the early 1990s mice were not the reliable optical devices we have today, instead they had nasty mechanical connections inside, or if you were extremely lucky, optical encoder wheels. It might sound like a rather unexpected device to produce, but we can see it fills an important niche.

He’s created, and it takes the form of a little PCB with an AT90S2313P microcontroller to do the translation and an RS232 level converter chip. Happily, has come along with a solution for those of you with a need to drive an ancient PC with a serial mouse. Want to run Windows 3.1 on a 386DX? Snes 1 Chip It is unlikely then that you could take a modern USB-only device and an unholy chain of USB-to-PS/2-to-serial adapters, and have it work as a serial mouse. Those mice from a decade or more ago would have contained the software to recognise the interface into which they were plugged, and emulate it accordingly. And if you were to go back a few more years into the past, you’d have found when you bought a mouse with a PS/2 connector fitted, it may well have come with an adapter for a 9-pin RS232 serial port. When did you last buy a mouse? Did it have a little adapter in the box? There was a time when if you bought a USB mouse, in the box was also an adapter to allow it to be used with the older PS/2 interface. I found a US SNES on ebay that appears to be a 1 Chip, with a serial number of UN316487083.

Snes 1 chip serial number