On Mon, Jan 10, 2000 at 01:39:07AM -0600, [EMAIL PROTECTED] wrote:
> Still trying to get somewhere with the modem on the 486 w/w3x
> Can't find a way to disable com ports, nothing in bios, nothing on MoBo,
> and can't get specs on the controller card
It's tedious, but you could work your way through the
jumpers on the controller card, changing one jumper at a
time, until you see which one frees up the port you want.
For a job like that it's nice if your diagnostic that
reports the com ports back to you is fast - debug is handy
for that. Here's how to use it for peeking on the ports:
-----
Using DEBUG to determine available Com Port address
This describes how to use DEBUG from DOS to find an available Com Port
address for your Internal Modem or Fax/Modem.
With the modem removed from the system, boot the machine with a plain
DOS boot disk. One with no AUTOEXEC.BAT and CONFIG.SYS.
Change your prompt to the DOS directory and type DEBUG and press
<RETURN>.
At the Dash Prompt type D 40:0. Debug will generate an entire
paragraph of addresses, for our purposes we will only use the first
half of the first line.
This portion denotes the COM addresses. This diagram describes how
your screen should look.
C:\DOS>DEBUG
-D 40:0
0040:0000 F8 03 F8 02 E8 03 E8 02-
Explanation:
0040:0000 Location Address Byte and Offset
F8 03 inverted is COM1 03F8h
F8 02 inverted is COM2 02F8h
E8 03 inverted is COM3 03E8h
E8 02 inverted is COM4 02E8h
If any of these sets of addresses are zeros then the com port is
available for
use by your Internal Modem or Fax/Modem. Below is a possible
scenario:
Your computer has two serial ports installed. You have a mouse on
COM1
and COM2 is not being used by a device. Running DEBUG gives you the
following results.
0040:0000 F8 03 F8 02 00 00 00 00-
0040:0000 Location Address Byte and Offset
F8 03 inverted is COM1 03F8h
F8 02 inverted is COM2 02F8h
The zeros located in COM3 and COM4 spots denote the absence of those
ports.
You have these address open to use for your modem. Set the modem for
COM3
or COM4 along with the appropriate IRQ and install your software.
The following chart displays the possible options when running DEBUG.
If DEBUG says this... You have this installed.
0040:0000 F8 03 00 00 00 00 00 00- COM1
0040:0000 F8 02 00 00 00 00 00 00- COM2
0040:0000 E8 03 00 00 00 00 00 00- COM3
0040:0000 E8 02 00 00 00 00 00 00- COM4
0040:0000 F8 03 F8 02 00 00 00 00- COM1, COM2
0040:0000 F8 03 E8 03 00 00 00 00- COM1, COM3
0040:0000 F8 03 E8 02 00 00 00 00- COM1, COM4
0040:0000 F8 02 E8 03 00 00 00 00- COM2, COM3
0040:0000 F8 02 E8 02 00 00 00 00- COM2, COM4
0040:0000 E8 03 E8 02 00 00 00 00- COM3, COM4
0040:0000 F8 03 F8 02 E8 03 00 00- COM1, COM2, COM3
0040:0000 F8 03 F8 02 E8 02 00 00- COM1, COM2, COM4
0040:0000 F8 03 E8 03 E8 02 00 00- COM1, COM3, COM4
0040:0000 F8 02 E8 03 E8 02 00 00- COM2, COM3, COM4
0040:0000 F8 03 F8 02 E8 03 E8 02- COM1, COM2, COM3, COM4
It is important to have the modem removed from the system when running
DEBUG.
If you have two objects addressed for the same COM port you will only
see one address. DEBUG does not report conflicts, only what
addresses are being used.
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