My system is a Northgate Slimline with a Logitech serial Trackman on 
com2 and a cardinal 2450 modem on com3. Com1 is unused and I have no 
com4. My communications software is Flashlink Version 2.14a, which 
runs software-implemented MNP in the background.

I was unable to use ANY communication program during or after running
Windows 3.0 in 386 Enhanced mode, and the recommended changes to 
SYSTEM.INI produced no effect.
I have solved all my problems by placing PF.com in my root directory 
and adding the command "PF C13" to my autoexec.bat file. 
Next, I reconfiqured terminal and cardfile to recognize COM1, and made the 
following changes using SYSEDIT:

My WIN.INI settings are as follows:
COM1:=2400,n,8,1
COM2:=2400,n,8,1
COM3:=
COM4:=

Warning! DO NOT use the ports setting from Control panel! Leave COM3
alone!

My SYSTEM.INI settings are as follows:

com1base=3e8h
com2base=2f8h

Com1AutoAssign=2
Com2AutoAssign=2

Com1irq=4
com2irq=3
comirqsharing=false

Once again, COM3 is left unmentioned. Read your Sysini2.txt notepad
file before changing your SYSTEM.INI

Experiments to try:
I have my mouse.com loaded before I switch ports. You may wish to 
this, I believe Logitech suggests the mouse driver be loaded last.
My Flashlink software still recognizes COM3 as the modem port, 
regardless of Port Finders setting. I believe Procomm is the same.
Anyway, it works for me.
 Drop me a note -- Mike De Carlo [72220,2652]