Since you searched for "serial mouse pinout," you likely want to do something. Here are three practical projects.

plug an Apple serial mouse into a PC serial port without an active converter.

This article provides a deep dive into the serial mouse pinout, wiring diagrams, voltage requirements, and troubleshooting tips for legacy hardware.

Long ago, before conquered the world, a desktop wasn't complete without a heavy, beige mouse that clicked like a typewriter. This is the story of the Serial Mouse —a legend of 1990s computing. The Legend of "Old Beige"

Before the universal serial bus (USB) became standard in the late 1990s, the vast majority of computer mice connected via a connector, commonly (and incorrectly) called a "DB9" connector. This connector communicated with the computer using the RS-232 serial protocol .

Baud: 1200 or 2400 Data: 7 bits, 1 stop, no parity