A mouse for the Amstrad CPC. The CPC mousepack was distributed by the German company [[Reisware]].
The mouse itself is an MSX mouse, which was sold by different companies like Sony and Philips for the MSX computers:
https://www.msx.org/wiki/Sony_MOS-1
== Technical ==
As it is an MSX mouse you can find information how to read the mouse movements on an MSX here:
https://www.msx.org/wiki/Mouse/Trackball#Direct_usage_of_mouse
Now it's maybe possible to understanding the following (old text of this article) in a better way:...
The exact mechanism that defines when the hardware does output the next 4bit fragment is unknown. The software does manipulate row 9 & row 6 signals, which does somehow request and/or acknowledge the fragments. Looking at the [[Media:CPC Mousepack 2.0 disassembly.txt|disassembled software]], the hardware seems to work like so (not confirmed):
switch from row0 to row9 --> invoke reading X counter (after 200 clks: MSB, after another 200 clks: LSB)