From:  LARRY MOTYLINSKI

15:45:14
08-29-88
 
  Via:  GGM DataLink
  
   To:  ALL

Subj:  QB4 FIX for Comm ports

 Ref: Compiling RBBS with QuickBasic 4.0

The following will help you Quick Basic 4.0 users with comm port problems.
When you open a file, QB replaces the interrupt vector addresses of the comm
ports with an INT 0.  They do this so that if you try to open the comm port
while it's already open the program will fail with a communications port not
found message.  To reset the port use the following sub-routine, since QB4
doesn't always reset them for you...

UN.TRASH.COMM.PORT:
DEF SEG = &H40
POKE 0, 248: POKE 1, 3: POKE 2, 248: POKE 3, 2
DEF SEG
RETURN

This will set the original addresses of the comm ports back to what they were
before QB got hold of them.  Thanks Microsoft (you bums).  
It took me over a week to track down this bug, I hope that it will help 
some of you.

You're Welcome,

Larry Motylinski 
Troy, MI

GGM DataLink
313-937-8211