Editor’s take: One of the first upgrades I bought for my very first computer around the turn of the century was a Microsoft IntelliMouse Explorer. Its standout feature was IntelliEye, an optical tracking system that replaced the traditional mouse ball and afforded unprecedented precision with minimal maintenance.

The pointer shipped with a then-standard PS/2 port but also worked with USB when using the included adapter. What you may not know is that this small, green adapter was purely a mechanical component.

As Microsoft’s Raymond Chen recently explained, PS/2 and USB are completely different protocols that are not compatible in any way. The adapter simply connected one set of pins to another, but featured zero circuitry. Indeed, it was the mouse (or keyboard, or whatever other device you were trying to use) that did all the work.

Chen likened the adapter to those inexpensive electrical outlet adapters popular among international travelers. In those, the adapter just connects one set of prongs to a different standard. All of the “magic” happens in the appliance or the power brick you are attempting to use.

Note that this is true of the older, green adapters. New units are still being manufactured, although Chen is unsure if these feature any internal hardware that translates between the PS/2 and USB signaling protocols or if everything is still managed by the target device.

As for the IntelliMouse, Microsoft announced plans to create a modern version of the fan-favorite in 2017 and made good on the promise a few years later. A quick check of Microsoft’s online store, however, shows the device is currently “out of stock.” The same was true at Amazon and Best Buy, suggesting the device may have been discontinued.

For those set on picking one up – either a newer model or a vintage example, I was able to find several options available on eBay at prices that won’t break the bank. Adapters are also readily available for a couple of bucks each.

Image credit: Marcus Urbenz