Adding Communication ports


        AC.SYS can be inserted into your CONFIG.SYS file to add non-standard 
communication ports for use as COM1, COM2, COM3, or COM4.  If your serial card 
uses a hardware port address which your BIOS ROM does not know then that card 
will be unavailable to DOS,  The Weak Link  and  The $25 Network.  With this 
program you can give the BIOS its proper address.  Serial card port addresses 
are kept as follows: 

                word at 40h:0  = COM1
                        40h:2  = COM2
                        40h:4  = COM3
                        40h:6  = COM4


        This program merely "pokes" a proper port address to the appropriate 
memory address.  You must know your card's port address in order to use this 
program.  Usually, a card will have several different address options which are 
set via jumpers or DIP switches.  Your manual is usually a good place to find 
this information but I have found several Taiwanese manuals with bad 
information.  I have several boards which are almost identical but the later 
versions have COM3 at 1F8h even though the manuals clearly state the COM3 
address of the card is 2E8h.  Evidently the board was revised but not the 
manual.  

        Once you find out your hardware's port address then add AC.SYS to your 
CONFIG.SYS file (with the appropriate parameters) prior to The Weak Link or 
The $25 Network. For example: 

                       DEVICE=AC.SYS COM2=1F8 COM3=2E8
                       DEVICE=PM.SYS COM2                    <-- Weak Link

        This will add COM2 and COM3.  Characters can be entered in upper or 
lower case. You cannot add the ":" to the COM name and you cannot add a space 
before or after the "=" sign.  The port address must be a hex number.  If the 
port address you give is not found then an error message will be printed and 
that parameter will be skipped.  

        Also note that you can use this program to expand the number of 
available ports beyond COM4.  Immediately after the four communication port 
addresses are kept 4 parallel port addresses.  If you are using only LPT1 then 
you could use the LPT4 slot as COM8, LPT3 as COM7, and LPT2 as COM6.  It would 
be best to use COM8 first, then COM7, etc.  But remember that all port 
addresses must be different.  Also remember that a special DOS device driver 
must be written in order for DOS to use anything above COM2.  These extended 
ports are only available to programs which simply need to know port addresses, 
such as The Weak Link and The $25 Network.  


                                                Don Jindra
                                                Information Modes
                                                P.O. Drawer F
                                                Denton, Texas  76202
                                                Ph. 817-387-3339