Apparently around 2014 the vast majority of mouses and keyboards were dual-protocol, but in 2019 the first reports of them being USB-only started appearing. I suspect a lot of the cheapest mouse SoCs are still dual-protocol as they worked when first designed, and they just kept producing them without any changes.
Apparently around 2014 the vast majority of mouses and keyboards were dual-protocol, but in 2019 the first reports of them being USB-only started appearing. I suspect a lot of the cheapest mouse SoCs are still dual-protocol as they worked when first designed, and they just kept producing them without any changes.
Pinout and explanation of how they detect protocol here: https://retrocomputing.stackexchange.com/questions/28288/how...