Is that basically a PS2 to serial adapter?
No, it plugs into the Amiga mouse port, and lets you use a PS2 mouse as an Amiga mouse. You don't need any software for it to work, but you need the software to activate the middle mouse button, or scroll wheel.
You can get software from Aminet to let you use a mouse on the serial port, but it has to have the software running for the mouse to work.
Ed King