Assuming your card is set to 2f0 (adjust as needed)
boot to DOS
start debug.exe
at the - prompt, type "d 40:0" and press enter (no quotes)
the display will look something like this:
C:\>debug
-d 40:0
0040:0000 F8 03 F8 02 00 00 00 00-BC 03 78 03 78 02 C0 9F ..........x.x...
0040:0010 23 C8 F0 80 02 00 00 20-00 00 2C 00 2C 00 64 20 #...... ..,.,.d
0040:0020 20 39 34 05 30 0B 3A 27-30 0B 0D 1C 00 00 00 00 94.0.:'0.......
0040:0030 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
0040:0040 D1 00 C3 00 07 8B 3E E2-CA 03 50 00 40 1F 00 00 ......>...P.@...
0040:0050 00 0A 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
0040:0060 07 06 00 D4 03 29 30 0F-1C 00 F0 00 1E 1B 0E 00 .....)0.........
0040:0070 00 00 00 00 00 00 08 00-14 14 14 14 01 01 01 01 ................
-
The bytes above that say "F8 03" and "F8 02" are the base addresses for COM1 and COM2 respectively. The 2 sets of "00 00" following are the base addresses for COM3 and COM4. Since they are 00 00, that means COM3+4 are not installed.
Yours may or may not be different, depending on what other COM ports you may have in your machine that your BIOS has detected.
If you have no COM ports in your machine, you may find these first few bytes as all 00's.
What you want to do is add in the next available COM port and set the base address to where your UART is on the XTIDE.
So, if you have no other COM ports installed, you're going to add COM1, so type this:
-e 40:0
debug responds with:
0040:0000 00.
type in f0 and then press the space bar. Debug prints the next byte and a dot: 00.
type in 02 and then press enter.
You've just updated the 2 bytes in memory.
Repeat the above d 40:0 and the display should show your new byte changes.
to exit debug, type q and then enter. Start banacom and see what happens.
You will have to do this every time you reboot the machine. (a small .com program to do this for you is easy to write)
=====================================
that MIGHT be all you need to do to get banacom to see you have a COM port, at COM1, and its base address is 2f0.
If it still doesn't see it, we may have to adjust the equipment list results that come back from Int 11h. Report back with your findings and we'll go the next step.
As for the UART speed, the oscillator speed is printed right on the can itself. The high speed Oscillator is 7.3728MHZ according to the wiki. This is likely too fast for banacom to work with, as most COM programs back in the day topped out at 57.6k. If you can't configure the COM port to 460k baud, you won't be able to talk over it and you will have to get a slower oscillator. that's the next failure point after the 2 I've already covered here.