[Q] Problem Two: The dorky port expander only takes a PS/2 mouse and I have a
fairly new logitech serial mouse that I like. Is there a adapter to go from DB9
to PS/2? I have not been able to find one. I don't want to buy the port
expander till I know it will be useful... I am on a budget (read: poor
student). Perhaps somebody knows the pin mapping on the PS/2 and DB9 so that I
can make an adapter myself ...

[A] Date: Tue, 16 Jul 1996 17:12:55 +0200
From: Kristjan Plaetzer <kristjan@sepp.che.sbg.ac.at>

A normal serial mouse can not be used on the PS/2 mouse port. Even the
available "serial-to-PS/2" adapters do not help. The signals and the
protocol is too different. Only a PS/2 mouse does work on a PS/2 port. By
the way there are some kind of "combined-mice" just as Microsofts
"Serial/Mouse Port Compatible Mouse 2.0" (Nr. 58264) and Logitechs MouseMan
M-CJ13 and TrackMan T-CC2-9F. The owner of such a Logitech-mouse can use a
Sub-D-plug. Here is the pin-mapping for such an adapter:

       6 # 5                 1 2 3 4 5
      4     3                 6 7 8 9
       2   1
  
  PS/2           Sub-D-plug for Logitech

    1 -------------------- 9 (Data)
    3 -------------------- 5 (Gnd)
    4 -------------------- 8 (+5 V)
    5 -------------------- 1 (Clock)

The diagram shows the view onto the contacts and not onto the soldering
side. This special solution is only possible for those two Logitech-types,
no other serial mouse is able to use the PS/2 signals.

Kristjan Plaetzer

[A]Subject: Mouse pin diagrams 
Date: Wed, 19 Jun 1996 16:18:48 -0400
From: Reed Wade 

http://csgrad.cs.vt.edu/~tjohnson/pinouts/

is a fine collection of pinouts and likely has what you
need whether it's a sun2 vme connector or something useful

[A]From: Philip Wilk
Beware of the serial to PS/2 adapters. They do not always work, from 
experience I know that the brand of mouse is an important variable.