The late 90's PS/2 stuff eventually lost serial compatibility, so make sure you have one that does do both.

The top one is marked serial and PS/2 mouse port compatible, the bottom one (probably) is PS/2 only already:

I have a couple of these guys, but no such adapter, unfortunately. Nice mice.

I tried one adapter on one of my microsoft PS/2 mouse but it didn't work. On the other hand I've got the exact same mouse with a serial connector (with a mousewheel ! That seems rather rare for a serial mouse !)

@firage - I have the exact one from the top picture, serial-mouse port compatible mouse 2.0

@Deksor, you can help me big time if you have a multimeter and you are willing to open up your mouse to check where each wire from this connector goes into the DB9 serial connector:

Thanks in advance!!!

What I can tell you is my "Serial Mouse 2.0A" is a four wire deal:

Thanks, I will try this pinout tomorrow, using only four wires - white to yellow. I don't have high hopes though, yours is quite different from mine.

If the serial mouse's color code does hold up, the following should check out based on adapter stuff around the web:
-White: PS/2 pin 4 (Vcc), serial RTS (=power).
-Blue: PS/2 pin 3 (ground), serial ground.
-Orange: PS/2 pin 2 (passthrough), serial data receive.
-Yellow: PS/2 pin 6 (passthrough), serial data transmit.
-Red/black: PS/2 pin 5 (data)/pin 1 (clock), not connected for serial.

Tried today, didn't work. Also, my mouse is wired the following way:

Black - Pin 1 (data)
Yellow - Pin 3 (GND)
Orange - Pin 4 (Vcc)
Red - Pin 5 (clk)
Blue - Pin 2 (unknown/serial?)
White - Pin 6 (unknown/serial?)

Yeah, for some reason the colors are definitely switched around.

Try this pinout: http://s505763140.onlinehome.us/shopqvs/ds/CC2022AC_S.jpg
The serial end looks good.

That's the first one I tried. Together with your serial mouse 2.0-inspired I think I tried 6 different pinouts. Mouse works when connected to PS/2 port (on another computer, my 486 doesn't know PS/2).
Thanks for your help, but I think I'm gonna give up on this.

I'm using one of those glossy mice, with a wheel, and it only works when I'm using an adapter branded "microsoft 68666".

Cool cOkebOttle, I'm going to get a hold of the adapter you mentioned to see if it will help. I have two MS mice, one which is serial compatible, but none of my adapters have worked.

Hello Vogoners , i have just fixed my ms mouse bought back in 1998 and i would like to ask you if you still need the schematics from the adaptor.I can do you a mapping if you nedd it ,take a look at the mouse to find out if it is the version you also have.thank you . Microsoft intelimouse serial ps2 saga.