Advantech RMD-1150 - Manual (Page 38)

- TechNote -
Subject:
Automatic serial mouse and PS/2 mouse conversion
Symptom: PS/2 mouse does not work at all.
Cause:
As per IMB PC spec, there are two pins (# 2 and # 6) in PS/2 mouse connector left
unconnected. These two pins are used for serial mouse identification and communication.
However, very few motherboard designers ignore the spec and ground these pins.
Therefore, when that computer boots up, the NovaView mistakenly identifies the mouse to be
serial mouse.
Solution:
1. If you are using the 3-in-1 cables, just swap the keyboard cable with mouse cable. Why?
There are 4 wires in the keyboard cable and 6 wires in the mouse cable. By swapping the
cables, the two unused pins become not connected.
2. If you are not using the 3-in-1 cables, just use a 4-wire PS/2 cable to connect from the PC
to the KVM switch. You may check if the cable has only 4 wires with a multimeter.
3. If that cable has 6 wires in it, you need some violence to solve this problem by pulling out
those two EXTRA pins from the PS/2 mouse connector from that computer. Please refer
to the diagram below, it is seen into the connector on the cable. You shall find 6 pins in it.
Note: I prefer solving such problem with some violence than any kind of design change. Much like kickin g your car to get the
engine starts.