OSMKPORT - DETERMINING IF OS/2 IS RECOGNIZING COM PORTS, AND
           RUNNING DEBUG
01/04/96

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    Determining if OS/2 Is Recognizing COM Ports, and Running DEBUG
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Please Read Entire Document for Full Explanation of Procedure
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DESCRIPTION

Experiencing modem and COM-port problems.

RESOLUTION

Determining if OS/2 Is Recognizing COM Ports
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1. Type MODE COMx and press Enter (x is 1 for COM port 1, 2 for COM
   port 2, and so on). The following information should be returned:

      BAUD       = 1200         PARITY     = EVEN
      DATABITS   =  7           STOPBITS   = 1
      TO         = OFF          XON        = OFF
      IDSR       = OFF          ODSR       = OFF
      OCTS       = OFF          DTR        = ON
      RTS        = ON           BUFFER     = AUTO

   If the information is correct, the COM port is recognized.

   Note: A 16550 UART is recommended for high-speed serial
         communications.


2. Type ECHO ATA>COM1 and press Enter to test a modem on COM1.

   If the modem makes high-frequency sounds or clicks, OS/2 is
   recognizing the modem. The problem might be with the application you
   are using.

If the COM port is not seen, use DEBUG to determine if the port
addresses are in the correct position or if the COM ports are just not 
installed. If the COM ports are not installed, an IRQ conflict could 
exist, or parameters are not being passed to COM.SYS.

Running DEBUG
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1. From an OS/2 or DOS window, type DEBUG and press Enter.

2. At the prompt, type D 40:00 and press Enter. Data appears on the
   screen.

3. Read the following to determine the data you need; then type Q and
   press Enter to exit.

The data that appears on the screen consists of:

* Addresses on the left
* Hexadecimal pairs denoting values of different locations
* ASCII representations on the right

The hexadecimal data consists of two sections divided by a dash ("-"). 
Each section consists of 8 hexadecimal pairs representing 4 values. 
The COM-port information, which is what you're looking for, is in the 
left section of the first line. If all 4 COM ports are installed, the 
section reads:

   0040:0000 F8 03 F8 02 E8 03 E8 02

The first pair of values following 0040:0000 represents COM1, the
second pair, COM2, and so on. The data is listed in Major/Minor code 
sequence, which results in an address of 3F8, for example, being 
expressed as F8 03. So the addresses for the COM ports are:

* COM1: 3F8 
* COM2: 2F8
* COM3: 3E8
* COM4: 2E8

If any pair is 00 00, that COM port is not installed.

Note: The OS/2 mouse driver masks the port address. So if 00 00
      appears, check to see if the mouse is installed in that port.
      A mouse that connects to the mouse port, or a bus mouse (one that
      has its own adapter), typically does not use a COM port.

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