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Communication Ports

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by kashmeir63

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Hi,
I have a windows nt4.0 server w/a internal modem on com3 port. When I go in the control panel under ports I see I have com1-com3.On the outside of the server I have 2 com ports. I tried hooking a device on to one of the external ports, and that worked fine. But that stopped my internal modem from working. I tried the other external port w/the same problem. I guess my question is how can I get the other device I'm hooking up to work on a different com port. The device I'm hooking up works fine on com1. Not sure how to get the device on to com 2.. Any help would be a plus....Hope this makes sense.

5 replies

by thechas

COMM ports 1 and 3 share some resources.

If you need the external device to function on COMM 1, you need to change the modem over to COMM 4.

Go to control panel / modems
Select your modem, and select properties.
Change the COMM port to COMM 4

That should take care of things.

Chas

by fenaikh

Hi
usually you have one or 2 comm ports as phisycal (hardware) ports in your case but if you need more phisycal (hardware) comm ports to connect driectly to an external device then you have to buy a special hardware a board which is inserted in a slot to get more ports. But in your case you do not need it since you have 2 ports com1 and com2. Comm ports reserve IRQ 3 and 4 where they can share an IRQ so comm ports 1,3,5 .. and so on odd numbers take IRQ 4 in the otherhand comm ports 2,4,6 .. and so on even numbers take IRQ 3. What makes all these ports works to gother is they should have different I/O adress. In the case with modems since you say you set it to com3 this is a virtual comm port in your modem it talk the IRQ4 and the I/O addres is probporly the same with com1 so you need to change the I/O address of ether com1 from the BIOS or your com3 (modem) from the modem setting. The COM2 may be is disable at BIOS so go to BIOS setting then enable it since you do not see it in the control panel under ports. The other possible thing you should check for your device it after you enable your com2 from BIOS is that device if it need seting to use the com2 ports.

note:
Possible I/O address for comm ports.
3F8H, 2F8H, 3E8H, and 2E8H

Good luck

Mohamed

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