More than 2 NT4 serial ports

Posted on 1997-08-04
Last Modified: 2013-12-14
Under NT3.51 I installed an I/O card (KW-557A) configured
as follows:
      IRQ Addr
COM3   9  3e8
COM4  12  2e8
LPT2  15  278
and my system came with
LPT1   7  378
COM1   4  3f8 (mouse)
COM2   3  2f8 (serial port with a modem attached)

Everything worked (except LPT2, which I didn't try).
Then I upgraded to NT4.0, and COM3 and COM4 were no longer
recognized.  I've read about sharing IRQ 3 and 4 with
COM4 and COM3, resp.  Is this the only solution?  I don't
want to have to disable drivers for devices on COM1 and 2
to use COM3 and 4, though I could manage not to actually
have bits flying simultaniously on two ports sharing an IRQ.
It would be far far better if I could get things going
as I had under 3.51, perhaps by assigning different IRQs
to COM3 and 4.  Or some other hack.  Suggestions?  I'll
buy another I/O card if I have to, but the present one has
a lot of jumper options.

PS I append the part of the diagnostics that I think
might be relevant for the current NT4 system.

IRQ and Port Report
Devices                       Vector Level  Affinity
i8042prt                           1     1 0xffffffff
Serial                             3     3 0x00000000
Elnk3                             10    10 0x00000001
Floppy                             6     6 0x00000000
opl3sa                            55     7 0x00000001
Sermouse                           4     4 0xffffffff
Aha154x                            0    11 0x00000000
atapi                              0    14 0x00000000
Devices                       Physical Address  Length
i8042prt                        0x00000060  0x0000000001
i8042prt                        0x00000064  0x0000000001
Parport                         0x00000378  0x0000000003
Serial                          0x000002f8  0x0000000007
Elnk3                           0x00000110  0x0000000001
Elnk3                           0x00000300  0x0000000010
Floppy                          0x000003f0  0x0000000006
Floppy                          0x000003f7  0x0000000001
opl3sa                          0x00000530  0x0000000004
opl3sa                          0x00000388  0x0000000004
Sermouse                        0x000003f8  0x0000000007
Aha154x                         0x00000330  0x0000000004
atapi                           0x000001f0  0x0000000008
atapi                           0x000003f6  0x0000000001
Question by:chaynes052397
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Expert Comment

ID: 1767835
Oh, oh.

I am just about to try to add a 4 port serial card on my server.  I didn't think there would be a problem.  I better watch this one!

If there's something non-normal about doing this, whoever answers can also have some points from me.


Author Comment

ID: 1767836
I'm running NT4 Workstation, not Server, which might well make
a difference.  

The two serial ports of my current card would be adequate for my
current needs, if they worked.  But in the future I might well
need an additional port.  So I wouldn't mind buying a not-too-expensive card with more ports if I knew it would work
with NT4 Workstation.  I only paid $35 for my current card!

Expert Comment

ID: 1767837
 As far as I recall, you can use those ports...  NT SUCKS for sharing IRQs, so I would recommend having the ports the way they are...  I'll try checking NT tomorrow.  I think the ports can be manually added.
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Expert Comment

ID: 1767838
    Well, I'm a little lost on adding the lpt2, but if you go to the control panel and select ports, you can add your serial ports with your new configurations.  As for the parallel, my guess is to find a driver of some sort for NT to install a non-standard port.  I'm looking...

Author Comment

ID: 1767839
I went to the control panel and did all the right things under
NT3.51, and it worked.  But it doesn't work under NT4, though
control-panel/ports info is the same as it was under NT3.51.
Changing the IRQs as above on the board and the contro panel didn't help.  There must be some way to have more than 2 ports.
At this point I would be willing to buy a new board, as long as
it didn't cost over, say $200.   I only need a couple more ports.

MORE POINTS if anyone can help!
LVL 12

Expert Comment

ID: 1767840
This all just doesnt make sense...

Just set the adress/irq for the port, (use the standard com1-com4 adresses) and plug it in, NT _WILL_ detect it correctly (as long as you have told the PnP BIOS to release these interupts)

Author Comment

ID: 1767841
What's the PnP BIOS?
How do you explain that the transition from NT3.51 to NT4 caused
the ports to stop working?
What about the IRQ addresses?  Do I have the right ones?
Is it essential that the COM3 and $ double up on the COM1 and 2


Expert Comment

ID: 1767842

I couldn't wait for this mess to be straightned out.  I bought a 4 port card, installed it in my server running NT 4, sp3.

I now have 4 serial ports.  All of them work.  I have modems on 3 of them and the mouse on the fourth.

Suggest you look at conflicts again.   Also, notice that NT gives you a limited number of addresses for com ports.  Ensure that your card is set to them.

I know you're dying to know, so here:
The card is a STB 4 com port card.  Cost me 100 bucks US.  It's a 16 bit card that gives me the option to set IRQs to 8 selections.  I have mine set to:
Com1  IRQ 4  Addr 3F8
Com2  IRQ 3  Addr 2F8
Com3  IRQ 15  Addr 3E8
Com4  IRQ 2 (9)  Addr 2E8

IRQ 15 is sometimes used for the secondary IDE port.  Personally, I have no use for the IDE interface, especially on a server.  AST also uses it for the energy effecient BS that also has no place on a server.

Of course, ya gotta watch IRQ 9.  Some video cards also use it.

I disabled all com ports on the machine, looked at the resource list and made my determinations.

You say your card lets you change all the settings too.  You shouldn't have to buy a different card.

I guess if anything, I have verifyed that NT 4 will allow the use of 4 com ports.  So, don't give up.

Expert Comment

ID: 1767843
I forgot.  After I installed the board, I went to the ports in the control panel and added them.

If you have only one printer port, you should be able to use IRQ5.  That is, unless you have a sound card.  The whole world seems to think one printer is enough!  If you have no printers, that opens up IRQ7

Author Comment

ID: 1767844
Thanks, barthollis.  I got an STB 4-com card and it works.
I'm using IRQs 2 3 4 5 12 & 15 and addresses {1,2,3}{E,F}8.


Expert Comment

ID: 1767845
hi, there is a new solution for this problem.
if you have a board that can configure edge triggered interrupt for irq 3 and 4 than you can share this IRQ. the problem seems to be a loss of the second or overlayed interrupt.
Please check the possibilities of your hardware.

Author Comment

ID: 1767846
As noted in my last posting, my problem is solved.


Expert Comment

ID: 1767847
if this problem is solved then close it !!

Accepted Solution

barthollis earned 100 total points
ID: 1767848

Glad that STB board worked out for you.


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